Electrochemical devices and related articles, components, configurations, and methods

ABSTRACT

Articles containing electrodes and current collectors arranged such that at least one electrode can be electronically isolated from other components of the article and/or an electrochemical device, and associated systems and methods, are provided. In some cases, the articles contain substrates for which a change in volume of the substrate causes at least one electrode to become electronically isolated from other components of the article and/or an electrochemical device. In certain cases, heating the substrate causes the change in volume of the substrate. Articles and electrochemical devices containing electrodes, current collectors, heaters, and/or sensors and associated systems and methods, are also provided. Electrochemical devices containing electrodes and current collectors arranged in a folded configuration, and associated articles, systems and methods, are also provided.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/698,435, filed Mar. 18, 2022, and entitled “Isolatable Electrodes andAssociated Articles and Methods,” which is a continuation of U.S. patentapplication Ser. No. 16/724,586 (now U.S. Pat. No. 11,322,804), filedDec. 23, 2019, and entitled “Isolatable Electrodes and AssociatedArticles and Methods,” which claims priority under 35 U.S.C. § 119(e) toU.S. Provisional Patent Application No. 62/785,332, filed Dec. 27, 2018,and entitled “Isolatable Electrodes and Associated Articles andMethods.” U.S. patent application Ser. No. 17/698,435, filed Mar. 18,2022, and entitled “Isolatable Electrodes and Associated Articles andMethods”; U.S. patent application Ser. No. 16/724,586 (now U.S. Pat. No.11,322,804), filed Dec. 23, 2019, and entitled “Isolatable Electrodesand Associated Articles and Methods”; U.S. Provisional PatentApplication No. 62/785,332, filed Dec. 27, 2018, and entitled“Isolatable Electrodes and Associated Articles and Methods”; U.S. patentapplication Ser. No. 16/724,596, filed Dec. 23, 2019, and entitled“Electrodes, Heaters, Sensors, and Associated Articles and Methods”;U.S. Provisional Application No. 62/785,335, filed Dec. 27, 2018, andentitled “Electrodes, Heaters, Sensors, and Associated Articles andMethods”; U.S. patent application Ser. No. 16/724,612, filed Dec. 23,2019, and entitled “Folded Electrochemical Devices and AssociatedMethods and Systems”; and U.S. Provisional Application No. 62/785,338,filed Dec. 27, 2018, and entitled “Folded Electrochemical Devices andAssociated Methods and Systems” are each incorporated herein byreference in its entirety for all purposes.

TECHNICAL FIELD

Articles, devices, systems, and methods related to the configuration ofelectrodes, current collectors, and/or substrates in electrochemicaldevices are generally described.

BACKGROUND

Typical batteries or battery packs include electrochemical cellscontaining anodes and cathodes that participate in chemical reactions.Batteries containing multiple electrochemical cells are typicallyconfigured with a stacked arrangement involving multiple discreteanodes, cathodes, and current collectors. Such stacked configurationscan be difficult or uneconomical to manufacture, and powering anexternal device through an external circuit with stacked configurationsrequires the formation of numerous separate electrical connections.Moreover, problems with individual electrodes or cells (such as shortcircuits) in batteries containing multiple electrochemical cells withtypical arrangements can lead to a propagation of failure or eventhermal runaway from the initial problematic cell to other cellsthroughout the entire battery, which can rapidly deteriorate theperformance of the battery and even create safety hazards. Additionally,in some cases, it may be desirable to maintain or change the temperatureof the battery, as well as detect changes in temperature or pressureduring operation of the battery.

Accordingly, improved articles, devices, systems, and methods aredesirable.

SUMMARY

Articles containing electrodes and current collectors arranged such thatat least one electrode can be electronically isolated from othercomponents of the article and/or an electrochemical device, andassociated devices, systems and methods, are provided. In some cases,the articles contain substrates for which a change in volume of thesubstrate causes at least one electrode to become electronicallyisolated from other components of the article and/or an electrochemicaldevice. In certain cases, heating the substrate causes the change involume of the substrate.

Articles and electrochemical devices containing electrodes, currentcollectors, heaters, and/or sensors and associated systems and methods,are also provided. The sensors, when present, may be temperature sensorsor pressure sensors. In some cases, the heaters and/or sensors areadjacent to the article or electrochemical device. In certain cases, theheaters and/or sensors are thin films that are integrated into thearticle or electrochemical device.

Electrochemical devices containing electrodes and current collectorsarranged in a folded configuration, and associated articles, systems andmethods, are also provided. In some cases, the electrochemical devicecontains one or more continuous components, such as a continuouselectrode, current collector, separator, and/or substrate. In somecases, the electrochemical device is constructed and arranged to applyan anisotropic force (e.g., in a direction normal to an anode activesurface). In certain cases, the electrochemical device contains anoversized anode.

The subject matter of the present invention involves, in some cases,interrelated products, alternative solutions to a particular problem,and/or a plurality of different uses of one or more systems and/orarticles.

In one aspect, an article is provided. In some embodiments, the articlecomprises a substrate. In some cases, the article comprises a pluralityof discrete electrode segments adjacent to the substrate. The electrodesegments may comprise electrode active material. In some embodiments,the article comprises a current collector domain. The current collectordomain may comprise a current collector bus electronically coupled tothe discrete electrode segments. In some embodiments, the currentcollector domain comprises a plurality of current collector segments.Each current collector segment may be electronically coupled to anelectrode segment. In some embodiments, for each of the currentcollector segments, the current collector segment is electronicallycoupled to the current collector bus via at least one current collectorbridge.

In another aspect, an article is provided. In some embodiments, thearticle comprises a substrate. In some cases, the article comprises aplurality of discrete electrode segments adjacent to the substrate. Theelectrode segments may comprise electrode active material. In someembodiments, the article comprises a current collector domain. Thecurrent collector domain may comprise a current collector buselectronically coupled to the discrete electrode segments. In someembodiments, the article is configured such that when the temperature ofthe article reaches a threshold temperature, at least one of theelectrode segments is no longer electronically coupled to the currentcollector bus due, at least in part, to a heat-induced change in volumeof the substrate.

In another aspect, a method is provided. In some embodiments, the methodcomprises changing a volume of a substrate that is part of anelectrochemical device during charging and/or discharging of theelectrochemical device. In some cases, the electrochemical devicecomprises a substrate. In certain cases, the electrochemical devicecomprises a plurality of discrete electrode segments adjacent to thesubstrate. The electrode segments may comprise electrode activematerial. In some embodiments, the electrochemical device comprises acurrent collector domain comprising a current collector buselectronically coupled to the discrete electrode segments. In someembodiments, the changing the volume of the substrate induces, at leastin part, a loss of electronic coupling between at least one of theelectrode segments and the current collector bus.

In another aspect, an article is provided. In some embodiments, thearticle comprises a substrate. In some cases, the article comprises aplurality of discrete electrode segments adjacent to the substrate. Theelectrode segments may comprise electrode active material. In someembodiments, the article comprises a current collector domain. In somecases, the current collector domain comprises a current collector buselectronically coupled to the discrete electrode segments. In someembodiments, the article comprises a heater adjacent to the substrate.In certain cases, the heater is configured to heat at least a portion ofthe article.

In another aspect, an article is provided. In some embodiments, thearticle comprises a substrate. In some cases, the article comprises aplurality of discrete electrode segments adjacent to the substrate. Theelectrode segments may comprise electrode active material. In someembodiments, the article comprises a current collector domain. In somecases, the current collector domain comprises a current collector buselectronically coupled to the discrete electrode segments. In someembodiments, the article comprises one or more sensors adjacent to thesubstrate. In certain cases, the one or more sensors is configured torespond to a condition of the article.

In another aspect, a method is provided. In some embodiments, the methodcomprises heating at least a portion of an electrochemical device usinga heater that is a part of the electrochemical device. In some cases,the electrochemical device comprises a substrate. In some embodiments,the electrochemical device comprises a plurality of discrete electrodesegments adjacent to the substrate. The electrode segments may compriseelectrode active material. In some embodiments, the electrochemicaldevice comprises a current collector domain. In some cases, the currentcollector domain comprises a current collector bus electronicallycoupled to the discrete electrode segments.

In another aspect, a method is provided. In some embodiments, the methodcomprises detecting a condition of an electrochemical device based, atleast in part, on a signal from a sensor that is a part of theelectrochemical device. In some cases, the electrochemical devicecomprises a substrate. In some embodiments, the electrochemical devicecomprises a plurality of discrete electrode segments adjacent to thesubstrate. The electrode segments may comprise electrode activematerial. In some embodiments, the electrochemical device comprises acurrent collector domain. In some cases, the current collector domaincomprises a current collector bus electronically coupled to the discreteelectrode segments.

In another aspect, an electrochemical device is described. In someembodiments, the electrochemical device comprises a first anode portioncomprising a first anode active surface portion. In some cases, theelectrochemical device comprises a second anode portion comprising asecond anode active surface portion, the second anode active surfaceportion facing the first anode active surface portion. In someembodiments, the electrochemical device comprises a third anode portioncomprising a third anode active surface portion. In some cases, thethird anode active surface portion is facing away from both the firstanode active surface portion and the second anode active surfaceportion. In some embodiments, the electrochemical device comprises afourth anode portion comprising a fourth anode active surface portion.In some cases, the fourth anode active surface portion is facing boththe first anode active surface portion and the third anode activesurface portion. In certain cases, the third anode portion is at leastpartially positioned between the first anode portion and the fourthanode portion. In some embodiments, the electrochemical device comprisesa first cathode portion comprising a first cathode active surfaceportion facing the first anode active surface portion. In someembodiments, the electrochemical device comprises a second cathodeportion comprising a second cathode active surface portion facing thesecond anode active surface portion. In some cases, the electrochemicaldevice comprises a third cathode portion comprising a third cathodeactive surface portion facing the third anode active surface portion. Insome cases, the electrochemical device comprises a fourth cathodeportion comprising a fourth cathode active surface portion facing thefourth anode active surface portion. In some embodiments, theelectrochemical device comprises a separator arranged such that a firstportion of the separator is between the first anode portion and thefirst cathode portion, a second portion of the separator is between thesecond anode portion and the second cathode portion, a third portion ofthe separator is between the third anode portion and the third cathodeportion, and a fourth portion of the separator is between the fourthanode portion and the fourth cathode portion. In some embodiments, theelectrochemical device is constructed and arranged to apply, during atleast one period of time during charge and/or discharge of the device,an anisotropic force with a component normal to the first anode activesurface portion.

In another aspect, an electrochemical device is described. In someembodiments, the electrochemical device comprises a plurality of anodeportions, a plurality of cathode portions, and a serpentine separator.In some embodiments, the electrochemical device comprises the followingarranged in the order listed: a first anode portion comprising a firstanode active surface portion; a first separator portion; a first cathodeportion comprising a first cathode active surface portion; a secondcathode portion comprising a second cathode active surface portion; asecond separator portion; a second anode portion comprising a secondanode active surface portion; a third anode portion comprising a thirdanode active surface portion; a third separator portion; a third cathodeportion comprising a third cathode active surface portion; a fourthcathode portion comprising a fourth cathode active surface portion; afourth separator portion; and a fourth anode portion comprising a fourthanode active surface portion. In some embodiments, the electrochemicaldevice is constructed and arranged to apply, during at least one periodof time during charge and/or discharge of the device, an anisotropicforce with a component normal to the first anode active surface portion.

In another aspect, an electrochemical device is described. In someembodiments, the electrochemical device comprises a first anode portioncomprising a first anode active surface portion. In some cases, theelectrochemical device comprises a second anode portion comprising asecond anode active surface portion, the second anode active surfaceportion facing the first anode active surface portion. In someembodiments, the electrochemical device comprises a third anode portioncomprising a third anode active surface portion. In some cases, thethird anode active surface portion is facing away from both the firstanode active surface portion and the second anode active surfaceportion. In some embodiments, the electrochemical device comprises afourth anode portion comprising a fourth anode active surface portion.In some cases, the fourth anode active surface portion is facing boththe first anode active surface portion and the third anode activesurface portion. In certain cases, the third anode portion is at leastpartially positioned between the first anode portion and the fourthanode portion. In some embodiments, the electrochemical device comprisesa first cathode portion comprising a first cathode active surfaceportion facing the first anode active surface portion. In someembodiments, the electrochemical device comprises a second cathodeportion comprising a second cathode active surface portion facing thesecond anode active surface portion. In some cases, the electrochemicaldevice comprises a third cathode portion comprising a third cathodeactive surface portion facing the third anode active surface portion. Insome cases, the electrochemical device comprises a fourth cathodeportion comprising a fourth cathode active surface portion facing thefourth anode active surface portion. In some embodiments, theelectrochemical device comprises a separator arranged such that a firstportion of the separator is between the first anode portion and thefirst cathode portion, a second portion of the separator is between thesecond anode portion and the second cathode portion, a third portion ofthe separator is between the third anode portion and the third cathodeportion, and a fourth portion of the separator is between the fourthanode portion and the fourth cathode portion. In some embodiments, theelectrochemical device comprises a cumulative cathode active surfaceperimeter defined by the sum of the perimeters of all cathode activesurfaces of the electrochemical device. In some cases, at least 60% ofthe cumulative cathode active surface perimeter is overlapped by anodeactive surface.

In another aspect, an electrochemical device is described. In someembodiments, the electrochemical device comprises a plurality of anodeportions, a plurality of cathode portions, and a serpentine separator.In some embodiments, the electrochemical device comprises the followingarranged in the order listed: a first anode portion comprising a firstanode active surface portion; a first separator portion; a first cathodeportion comprising a first cathode active surface portion; a secondcathode portion comprising a second cathode active surface portion; asecond separator portion; a second anode portion comprising a secondanode active surface portion; a third anode portion comprising a thirdanode active surface portion; a third separator portion; a third cathodeportion comprising a third cathode active surface portion; a fourthcathode portion comprising a fourth cathode active surface portion; afourth separator portion; and a fourth anode portion comprising a fourthanode active surface portion. In some embodiments, the electrochemicaldevice comprises a cumulative cathode active surface perimeter definedby the sum of the perimeters of all cathode active surfaces of theelectrochemical device. In some cases, at least 60% of the cumulativecathode active surface perimeter is overlapped by anode active surface.

Other advantages and novel features of the present invention will becomeapparent from the following detailed description of various non-limitingembodiments of the invention when considered in conjunction with theaccompanying figures. In cases where the present specification and adocument incorporated by reference include conflicting and/orinconsistent disclosure, the present specification shall control.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting embodiments of the present invention will be described byway of example with reference to the accompanying figures, which areschematic and are not intended to be drawn to scale. In the figures,each identical or nearly identical component illustrated is typicallyrepresented by a single numeral. For purposes of clarity, not everycomponent is labeled in every figure, nor is every component of eachembodiment of the invention shown where illustration is not necessary toallow those of ordinary skill in the art to understand the invention. Inthe figures:

FIG. 1 is an exemplary schematic illustration depicting a top-down viewof an article, according to certain embodiments;

FIG. 2A is an exemplary schematic illustration depicting a top-down viewof an article, according to certain embodiments;

FIG. 2B is an exemplary schematic illustration depicting across-sectional side view of an article, according to certainembodiments;

FIG. 2C is an exemplary schematic illustration depicting a side view ofan article, according to certain embodiments;

FIG. 3 is an exemplary schematic illustration depicting a top-down viewan article, according to certain embodiments;

FIG. 4 is an exemplary schematic illustration depicting across-sectional side view of an electrochemical device, according tocertain embodiments;

FIG. 5 is an exemplary schematic illustration depicting across-sectional side view of an article, according to certainembodiments;

FIG. 6A is an exemplary schematic illustration depicting a side view ofan electrochemical device, according to certain embodiments;

FIG. 6B is an exemplary schematic illustration depicting a side view ofan electrochemical device, according to certain embodiments;

FIG. 7A is an exemplary schematic illustration depicting a side view ofa part of an article, according to certain embodiments;

FIG. 7B is an exemplary schematic illustration depicting a side view ofa part of an article, according to certain embodiments;

FIG. 8A is an exemplary schematic illustration depicting a side view ofa part of an article, according to certain embodiments;

FIG. 8B is an exemplary schematic illustration depicting a side view ofa part of an article, according to one set of embodiments;

FIG. 9A is an exemplary schematic illustration depicting across-sectional side view of a part of a partially unfoldedelectrochemical device, according to certain embodiments;

FIG. 9B is an exemplary schematic illustration depicting across-sectional side view of a part of a folded electrochemical device,according to one set of embodiments;

FIG. 10A is an exemplary schematic illustration depicting across-sectional side view of a part of a partially unfoldedelectrochemical device, according to certain embodiments;

FIG. 10B is an exemplary schematic illustration depicting across-sectional side view of a part of a folded electrochemical device,according to certain embodiments;

FIGS. 11A-11B depict a schematics showing cathode active surfaces andcathode active surface perimeters, according to certain embodiments; and

FIG. 12 depicts a schematic showing a cathode active surface and ananode active surface overlapping a certain at least some of theperimeter of the cathode active surface, according to certainembodiments.

DETAILED DESCRIPTION

Articles containing electrodes and current collectors arranged such thatat least one electrode can be electronically isolated from othercomponents of the article and/or an electrochemical device, andassociated devices, systems and methods, are provided. In some cases,the article comprises a substrate (e.g., a polymeric material), acurrent collector bus, and a plurality of discrete electrode segments(e.g., comprising an electrode active material such as lithium and/or alithium alloy) adjacent to the substrate and electronically coupled tothe current collector bus. At least some of the electrode segments maybe electronically decoupled from the current collector bus due at leastin part to change in volume of the substrate. Changing the volume of thesubstrate may, in certain cases, involve heating the article (e.g., tocause a heat-induced expansion or contraction of the substrate), therebyproviding a simple, economical way to electronically isolate electrodes(e.g., problematic electrodes such as those that are part of ashort-circuit). Configurations of the article described herein mayinclude the use of discrete current collector segments and currentcollector bridges electronically coupled to the current collector bus,and/or continuous components (e.g., continuous substrates and/orcontinuous current collector buses). The article may, in certainembodiments, comprise a heater and/or a sensor (e.g., a temperaturesensor or a pressure sensor) adjacent to the substrate. The articlesprovided herein may be useful when included in electrochemical devices(e.g., a multi-cell battery such as a rechargeable lithium battery). Thearticle may, in certain embodiments, comprise a heater and/or a sensor(e.g., a temperature sensor or a pressure sensor) adjacent to thesubstrate.

In certain cases, electrochemical devices (and articles containedtherein) can be arranged with a folded configuration, and can befabricated without the need for complicated and/or expensivemanufacturing procedures. In some such cases, the folded (or foldable)electrochemical devices are constructed and arranged to apply (e.g.,during at least one period of time during charge and/or discharge) ananisotropic force with a component normal a portion of theelectrochemical device (e.g., an anode active surface portion). Incertain cases, configurations of anodes and cathodes are employed tomitigate problems associated with certain anode active materials (e.g.,lithium or lithium alloy). For example, in some cases, foldedelectrochemical devices comprising “oversized” anodes are provided.

A common problem for multi-cell batteries comprising a plurality ofanodes and cathodes is the removal of problematic electrodes from theoverall electrical circuit before the problematic electrodes causesubstantial damage to the overall battery. One way in which an electrodemay become problematic is when it reaches too high a temperature (e.g.,due to the electrode participating in a short-circuit). Such problematicelectrodes can compromise the performance of the battery and presentsafety hazards such as thermal runaway (e.g., in the case of lithiumbatteries). Electrochemical devices for which electrodes can be simplyand easily electronically isolated (e.g., upon reaching a certaintemperature) without complex and expensive circuitry, arrangements,and/or fabrication procedures are therefore desirable. The articles,systems, and methods described herein, in accordance with certain butnot necessarily all embodiments, provide for simple, economical, andeffective ways for electronically isolating electrodes from currentcollectors (e.g., current collector buses) and/or other components. Forexample, arranging an article with a current collector bus and aplurality of discrete electrode segments adjacent to a substrate allows,in some cases, for a change in volume of the substrate (e.g., aheat-induced change in volume of the substrate) to electronicallydecouple at least one of the discrete electrode segments from thecurrent collector bus, therefore isolating the electrode segment fromthe system.

While typical batteries are constructed in a stacked configuration andtherefore require careful, expensive, and often wasteful fabrication andarrangement steps, the articles and electrochemical devices describedherein can, in certain cases, be arranged and constructed with certaincontinuous components such as continuous substrates, electrodes, currentcollectors, and/or separators. The use of some such continuouscomponents may reduce the expense and manufacturing time for batteriesand provide for configurations that can improve functionality. Forexample, a plurality of discrete electrodes can be electronicallycoupled to a continuous current collector bus, thereby providing asimple design for an article having electronically-isolatableelectrodes. Additionally, a battery having continuous components can, insome cases, be arranged to be folded instead of stacked, which canaccelerate fabrication, reduce cost, and increase tolerances. In somecases, an anisotropic force is applied to a folded electrochemicaldevice described herein. Additionally, in some, but not all embodiments,the electrodes of the folded electrochemical device are arranged andconfigured such that a relatively high proportion of the cumulativeperimeter of the cathode active surface is overlapped by anode, whichmay, in some cases, reduce certain problems such as over-utilization oruneven utilization during operation of the folded electrochemicaldevice.

In some embodiments, articles, devices, systems, and methods related tothe configuration of electrodes, substrates, current collectors, andrelated components are generally described. FIG. 1 includes a schematicillustration of article 100 according to one set of embodiments. Thearticle may, in certain cases, be used as a component in anelectrochemical device. The article may comprise multiple components,such as substrates, electrodes, and/or current collector domains ininventive configurations.

In some embodiments, the article comprises a substrate. Referring againto FIG. 1 , in some embodiments, article 100 comprises substrate 120. Insome embodiments, other components of the article, such electrodes,current collector domains, and the like may be disposed on thesubstrate. The substrate may be made of any of a variety of suitablematerials, such as materials that can undergo a change in volume, aswill be described in more detail below. In some embodiments, thesubstrate is a thin film (e.g., a thin polymeric film or a think ceramicfilm). The substrate may be a monolithic material, or the substrate maybe a composite of multiple layers. In certain embodiments, the substratecomprises at least one domain or layer that is electronicallynon-conductive. In some, but not necessarily all embodiments, thesubstrate is flexible (e.g., has sufficient flexibility to be foldedwithout undergoing substantial failure). In some, but not necessarilyall embodiments, the substrate is or comprises a release layer. Forexample, substrate 120 in FIG. 1 is a release layer, in accordance withcertain embodiments.

In some embodiments, the article comprises a plurality of discreteelectrode segments adjacent to the substrate. As shown in FIG. 1 ,article 100 comprises a plurality of discrete electrode segments 130adjacent to substrate 120. The electrode segments may be formed directlyon the substrate (e.g., via a deposition or coating process), or theremay be one or more intervening layers between the substrate and theadjacent electrode segments. The plurality of discrete electrodesegments adjacent to the substrate may be within a relatively smalldistance of the substrate (e.g., in embodiments involving compact,energetically dense designs). For example, each of the plurality ofdiscrete electrode segments may be within 5.0 mm, within 3.0 mm, within2.0 mm, within 1.0 mm, within 0.5 mm, within 0.3 mm, within 0.2 mm,within 0.1 mm, or less of the substrate. In some embodiments, each ofthe plurality of discrete electrode segments are anodes, and in someembodiments each of the plurality of discrete electrode segments arecathodes. In certain embodiments, the plurality of discrete electrodescomprises both cathodes and anodes.

In some embodiments, the electrode segments comprise an electrode activematerial. As used herein, the term “electrode active material” refers toany electrochemically active species associated with an electrode. Forexample, a “cathode active material” refers to any electrochemicallyactive species associated with the cathode, while an “anode activematerial” refers to any electrochemically active species associated withan anode. In some embodiments, the electrode segments comprise lithiummetal and/or a lithium alloy as an electrode active material (e.g., asan anode active material). Suitable cathode active materials and anodeactive materials are described more fully below.

As used herein, the use of the term “discrete” in relation to theplurality discrete electrode segments mentioned above refers to eachelectrode segment of the plurality of discrete electrode segments beingdistinct and spatially separated from the other electrode segments ofthe plurality of discrete electrode segments. For example, referring toFIG. 1 , the plurality of discrete electrode segments 130 compriseselectrode segment 130 a and electrode segment 130 b, and electrodesegment 130 a is distinct and spatially separated from electrode segment130 b. In some embodiments, the discrete electrode segments are arrangedsuch that the segments are not connected to each other via regionscomprising electrode active material. In some cases, no two discreteelectrode segments are in direct physical contact with each other whenthe article described herein is used as part of an electrochemicaldevice (e.g., a device containing one or more electrochemical cells whenloaded with electrolyte, such as a battery), even, for example, if andwhen the article is folded. Furthermore, any electronic coupling betweenany two discrete electrode segments involves the transport of electronsthrough at least one other component other than the coupled electrodesegments, such as the current collector domain of the article. Havingthe article comprise a plurality of discrete electrode segments, asopposed to a plurality of non-discrete electrode segments, in accordancewith certain embodiments, allows for individual electrode segments, incertain cases, to be electronically isolated from other components ofthe article, such as the other electrode segments and/or a currentcollector bus (described more fully below).

In some embodiments, the article comprises a current collector domain.For example, referring to FIG. 1 , article 100 comprises currentcollector domain 125 adjacent to substrate 120, according to certainembodiments. The current collector domain can collect the electroniccurrent generated by the plurality of discrete electrode segments, andcan provide an efficient surface for attachment of electrical contactsleading to an external circuit (e.g., when the article is used as partof an electrochemical device such as a battery). As such, the currentcollector domain typically comprises an electronically conductivematerial. For example, the current collector domain may comprise one ormore electronically conductive metals such as aluminum, copper,chromium, stainless steel, and nickel. In some embodiments, the currentcollector domain comprises a copper metal layer. In some instances, thecurrent collector domain includes multiple subdomains or substructures,the arrangement and/or configuration of which may be useful in allowingfor the electronic isolation of individual electrode segments of theplurality of discrete electrode segments (e.g., due to a change involume of the substrate). For example, the current collector domain maycomprise current collector segments and/or current collector bridges, asdescribed more fully below.

In some embodiments, the current collector domain comprises a currentcollector bus. FIG. 1 depicts current collector domain 125, whichcomprises current collector bus 121, according to certain embodiments.In some cases, the current collector domain is made entirely of thecurrent collector bus (as is the case shown in FIG. 1 , according tocertain embodiments), while in certain cases, the current collectordomain includes other structures in addition to the current collectorbus. The current collector bus may be the structure of the currentcollector domain to which electrical contact with an external circuit isformed (e.g., in the case of an electrochemical device such as abattery). In certain cases, the current collector bus is continuous, asis described in more detail below.

In some embodiments, the current collector bus is electronically coupledto the discrete electrode segments (e.g., from the plurality of discreteelectrode segments). For example, referring to FIG. 1 , article 100comprises a plurality of discrete electrode segments 130 and currentcollector domain 125 comprising current collector bus 121, and currentcollector bus 121 is electronically coupled to the plurality of discreteelectrode segments 130, according to certain embodiments. The electroniccoupling between the discrete electrode segments and the currentcollector bus can allow for electrical current generated at theelectrode segments to flow to the current collector bus, which may be inelectronic contact with an external circuit. The electronic couplingmay, in certain cases, be established by direct physical contact betweenthe discrete electrode segments and the current collector bus. Forexample, referring to FIG. 1 , the discrete electrode segments of theplurality of discrete electrode segments 130 are in direct physicalcontact with and consequently electronically coupled to currentcollector bus 121, in accordance with certain embodiments. However, insome cases, the electronic coupling between the discrete electrodesegments and the current collector bus occurs via one or more additionalintervening structures of the current collector domain, as will bedescribed more fully below.

In some cases, a loss of electronic coupling between the currentcollector bus and at least one of the discrete electrode segments of theplurality of discrete electrode segments can occur. Such a loss ofelectronic coupling can result in the at least one of the discreteelectrode segments being electronically isolated from the currentcollector bus, the other discrete electrode segments that have not lostelectronic coupling with the current collector bus, and/or components ofan external electrical circuit (e.g., other components of anelectrochemical device such as a battery). As mentioned above, isolationof certain electrode segments can be useful for removing problematicelectrodes from the overall circuit while allowing, for example, anelectrochemical device to continue to charge and/or discharge withadequate performance.

Some embodiments comprise changing a volume of a substrate that is partof an electrochemical device during charging and/or discharging of theelectrochemical device. The electrochemical device may comprise thearticle described herein, including the substrate described herein. Insome cases, changing the volume of the substrate induces, at least inpart, a loss of electronic coupling between at least one of theelectrode segments and the current collector bus. For example, referringto FIG. 1 again, in some cases, changing the volume of substrate 120 ofarticle 100 during charging and/or discharging of an electrochemicaldevice comprising article 100 induces, at least in part, a loss ofelectronic coupling between discrete electrode segment 130 a and currentcollector bus 121, according to certain embodiments. In such a way, thechanging of the volume of the substrate can be used to electronicallyisolate certain discrete electrode segments during charging and/ordischarge cycles (e.g., for safety reasons).

In some embodiments, changing the volume of the substrate comprisesincreasing the volume of the substrate. As an example and in accordancewith certain embodiments, in FIG. 1 , current collector bus 121 is alayer of conductive metal (e.g., copper) coated onto substrate 120, andthe plurality of discrete electrode segments 130 comprises discretelayers comprising electrode active material (e.g., lithium and/or alithium alloy) in direct physical contact with current collector bus121. When the volume of substrate 120 is increased (e.g., expanded), atleast one of the discrete electrode segments of the plurality ofdiscrete electrode segments 130 (e.g., discrete electrode segment 130a), may lose electronic coupling with current collector bus 121 due, atleast in part, to the increase in volume of the substrate (e.g., due tothe formation of a gap and consequent loss of direct physical contactbetween at least one of the discrete electrode segments and currentcollector bus 121).

In some embodiments, changing the volume of the substrate comprisesdecreasing the volume of the substrate. As an example and in accordancewith certain embodiments, in FIG. 1 current collector bus 121 is a layerof conductive metal (e.g., copper) coated onto substrate 120, and theplurality of discrete electrode segments 130 comprises discrete layerscomprising electrode active material (e.g., lithium and/or a lithiumalloy) in direct physical contact with current collector bus 121. Whenthe volume of substrate 120 is decreased (e.g., contracted/shrunk), atleast one of the discrete electrode segments of the plurality ofdiscrete electrode segments 130 (e.g., discrete electrode segment 130a), may lose electronic coupling with current collector bus 121 due, atleast in part, to the decrease in volume of the substrate (e.g., due todelamination of the at least one of the discrete electrode segments anda consequent loss of direct physical contact between the at least one ofthe discrete electrode segments and current collector bus 121).

In some cases, changing the volume of the substrate comprises heatingthe substrate. In other words, a change in volume of the substrate mayoccur due, at least in part, to a thermal expansion or contraction ofthe substrate. For example, referring to FIG. 1 , heating substrate 120(or a portion thereof) may cause a change in volume of substrate 120. Incertain cases, heating the substrate may comprise applying heat from aheater, which can either be a component external to the article orcomponent integrated into the article, as described more fully below.However, in some embodiments, heating the substrate comprises chargingand/or discharging an electrochemical device such that heat is generatedby the charging and/or discharging. For example, in some cases, a shortcircuit between at least one of the discrete electrode segments andanother component of an electrochemical device may occur, resulting in aresistive heating that heats and consequently changes the volume of thesubstrate.

It should be understood that in some cases, heating components of anelectrochemical device or an article described herein may cause a lossof electronic coupling between a discrete electrode segment and thecurrent collector bus due to melting or thermal shock of a component(e.g., a portion of the discrete electrode segment or a portion of thecurrent collector bus). While such a phenomenon may occur in some casesduring the heating of the substrate, embodiments described hereininvolve the loss of electronic coupling occurring at least in part dueto a change in volume of the substrate. Non-limiting causes of the lossof electronic coupling due to the change in the volume of the substrateare described in more detail below.

In some embodiments, the article described herein is configured suchthat, when the temperature of the article reaches a thresholdtemperature, at least one of the electrode segments is no longerelectronically coupled to the current collector bus due, at least inpart, to a heat-induced change in volume of the substrate. For example,referring to FIG. 1 , article 100 is configured such that, when article100 reaches a threshold temperature, at least one of the electrodesegments of the plurality of discrete electrode segments 130 (e.g.,discrete electrode segment 130 a) is no longer electronically coupled tocurrent collector bus 121, due, at least in part, to a heat inducedchange in volume of the substrate, according to some embodiments. As anon-limiting example, in some cases, the threshold temperature is 65° C.In such cases, if the temperature of the article rises (e.g., due to anexternal heat source and/or a short-circuiting of an electrochemicaldevice), once the temperature reaches 65° C., at least one of theelectrode segments will become electronically decoupled from the currentcollector bus due, at least in part, to a heat-induced change in volumeof the substrate.

The article may be configured to undergo a loss of electronic couplingbetween at least one of the discrete electrode segments and the currentcollector bus due, at least in part, to a heat-induced change in volumeof the substrate by, for example choosing certain components, such asthe substrate, to comprise one or more materials having a thermalexpansion coefficient with a relatively large magnitude. In addition oralternatively, the article can be configured to have a mismatch betweenthe thermal expansion coefficients of two or more components of thearticle (e.g., the substrate and one or more structures of the currentcollector domain), so that the two or more components expand atdifferent rates during the heating process, causing mechanical failureof a component and therefore loss of electronic coupling. One exemplaryconfiguration of an article that may, in some embodiments, undergo aloss of electronic coupling between at least one of the electrodesegments and the current collector domain when the temperature of thearticle reaches a threshold temperature is described in more detailbelow.

It should be understood that the threshold temperature at which, in someembodiments, a loss of electronic coupling between the discreteelectrode segments and the current collector domain occurs depends onthe materials used for the components of the article (e.g., thesubstrate, the electrode segments, the current collector domain, etc.),as well as the geometry and dimensions of the components. The thresholdtemperature is an absolute temperature at which the loss of electroniccoupling described herein and elsewhere occurs. It should be understoodthat the threshold temperature considered herein refers to thetemperature of one or more of the components of the article, not anambient temperature (e.g., the temperature of the surroundings orenvironment in which the article and/or electrochemical devicecomprising the article is located). In some embodiments, the thresholdtemperature is a temperature of the substrate of the article. In someembodiments, the threshold temperature is a temperature of the currentcollector domain. In some embodiments, the threshold temperature is atemperature of at least one of the plurality of discrete electrodesegments.

In some embodiments, the article is configured such that, uponundergoing a threshold temperature change, at least one of the electrodesegments is no longer electronically coupled to the current collectorbus due, at least in part, to a heat-induced change in volume of thesubstrate. The threshold temperature change is relative to a certaininitial temperature at which there are no internal mechanical stresses(e.g., compression, tension, shear, bending, torsion, etc.) in thearticle.

As mentioned above, in certain cases, the current collector domaincomprises multiple substructures that may be useful in electronicallyisolating one or more discrete electrode segments under certainconditions (e.g., upon a heat-induced change in volume of thesubstrate).

In some embodiments, the current collector domain comprises a pluralityof current collector segments. For example, FIG. 2A depicts article 100comprising current collector domain 125, wherein current collectordomain 125 comprises a plurality of current collectors segments,including current collector segment 122, in addition to currentcollector bus 121. As in the case of other structures of the currentcollector domain, the current collector segments comprise and/or aremade of electronically conductive materials, such as electronicallyconductive metals (e.g., copper). The current collector segments can bemade, for example, by performing a patterned deposition of theelectronically conductive material (e.g., as films) on to the substrate(e.g., a release layer), as is described below. In some embodiments, thecurrent collector segments are separated by voids or gaps. For example,in FIG. 2A, current collector segment 122 is separated from the closestneighboring current collector segment by a void in conductive material(in some cases, the void leaving a portion of substrate 120 exposed).The presence of voids or gaps between current collector segments allowsfor the current collector segments to be electronically isolated fromeach other, under certain conditions (e.g., upon a heat-induced changein volume of the substrate).

In some embodiments, each current collector segment is electronicallycoupled to an electrode segment. Referring again to FIG. 2A, article 100comprises a plurality of discrete electrode segments 130 includingdiscrete electrode segment 130 a, as well as a plurality of currentcollector segments including current collector segment 122, and currentcollector segment 122 is electronically coupled to discrete electrodesegment 130 a. The electronic coupling between a current collectorsegment and an electrode segment can allow for electrical currentgenerated at the electrode segment to flow to the current collectorsegment, which may electronically couple with other components of thecurrent collector domain, such as the current collector bus.

In some embodiments, for each current collector segment, the currentcollector segment is disposed, at least partially, between the substrateand the electrode segment to which the current collector segment iselectronically coupled. FIG. 2B depicts a side view of exemplary article100, where current collector segment 122 is disposed, at leastpartially, between electrode segment 130 a and substrate 120. Such aconfiguration can allow for a relatively large area of contact betweenthe electrode segment and the current collector segment, while stillleaving a relatively large active surface of the electrode segmentfacing away from the current collector segment available for use inapplications such as in an electrochemical device. As used herein, theterm “active surface” is used to describe a surface of an electrode thatcan be in physical contact with an electrolyte when the article is partof an electrochemical cell, and at which electrochemical reactions maytake place. Having a relatively large area of contact between theelectrode segment and the current collector segment can allow forefficient transfer of electrical current generated at the electrodesegment to the current collector domain.

In some embodiments, for each of the current collector segments, thecurrent collector segment is electronically coupled to the currentcollector bus via at least one current collector bridge. In other words,in some embodiments, any flow path of electrical current from thecurrent collector segments to the current collector bus must passthrough at least one current collector bridge. A current collectorbridge is a substructure of the current collector domain disposed, atleast partially, between a current collector segment and the currentcollector bus. FIG. 2A depicts a plurality of current collector bridges,including current collector bridge 123. Current collector bridge 123 isdisposed between current collector segment 122 and current collector bus121. FIG. 2B shows a side view of a cross-section of exemplary article100, for which current collector bridge 123 is disposed between currentcollector segment 122 and current collector bus 121. Current collectorsegment 122 is electronically coupled to current collector bus 121 viacurrent collector bridge 123, according to certain embodiments. Thecurrent collector bridges may comprise an electronically conductivematerial (e.g., an electronically conductive metal such as copper). Asin the case of the current collector segments, the current collectorbridges can be made, for example, by performing a patterned depositionof the electrically conductive material (e.g., as films) on to thesubstrate (e.g., a release layer). In some cases, the current collectorbridges have a relatively small thickness, as will be described morebelow. In some cases, each current collector bridge is in directphysical contact with an associated current collector segment as well asthe current collector bridge. However, in certain embodiments, otherintervening materials (e.g., electronically conductive materials) orstructures may be disposed, at least partially, between the currentcollector bridge and the associated current collector segment and/orcurrent collector bus.

In some embodiments, for each discrete electrode segment of theplurality of discrete electrode segments, the discrete electrode segmentis electronically coupled to the current collector bus via at least onecurrent collector segment. In other words, in certain embodiments, anyflow path of electrical current generated at a discrete electrodesegment of the plurality of discrete electrode segments to the currentcollector bus must pass through at least one current collector segment.For example, referring again to FIGS. 2A and 2B, any flow path ofelectrical current generated at discrete electrode segment 130 a (e.g.,during discharging of an electrochemical cell) to current collector bus121 must pass through current collector segment 122, according tocertain embodiments. In some cases, the article is configured such thatany flow path of electrical current generated at a discrete electrodesegment to the current collector bus must pass through both at least onecurrent collector segment associated with the discrete electrode as welland a current collector bridge that electronically couples the currentcollector segment to the current collector bus. For example, referringto FIGS. 2A and 2B, any flow of electrical current generated at discreteelectrode segment 130 a to current collector bus 121 must comprisetransporting electronic charge from discrete electrode segment 130 a tocurrent collector segment 122, transporting electronic charge fromcurrent collector segment 122 to current collector bridge 123, andfinally, transporting electronic charge from current collector bridge123 to current collector bus 121, according to certain embodiments. Somesuch configurations of the article described herein, involving discreteelectrode segments, current collector segments, and a current collectorbridges, each of which is electronically coupled to the currentcollector bus but separated, for example, by voids or gaps), may allowfor convenient electronic isolation of individual discrete electrodesegments (e.g., caused by changing the volume of the substrate andconsequently breaking a current collector bridge associated with thatdiscrete electrode segment).

In some embodiments, changing the volume of the substrate causes, atleast in part, at least one of the current collector bridges to nolonger couple the current collector segment associated with that currentcollector bridge to the current collector bus. Such a loss of electroniccoupling between a current collector segment and the current collectorbus may result in the loss of coupling between the discrete electrodesegment associated with the current collector segment and the currentcollector bus, thereby electronically isolating the electrode segment.For example, referring to FIG. 2A, changing the volume of substrate 120causes, at least in part, current collector bridge 123 to no longercouple current collector segment 122 to current collector bus 121,thereby electronically isolating discrete electrode segment 130 a. Achange in volume of the substrate may cause a current collector bridgeto no longer couple a current collector segment to the current collectorbus by causing, for example, mechanical failure of the current collectorbridge (e.g., fracturing caused by ultimate tensile or compressivefailure of the current collector bridge) or a physical separation of thecurrent collector bridge from one or both of the current collectorsegment and the current collector bus (e.g., via delamination).

As mentioned above, in some cases, changing the volume of the substrateinvolves heating the substrate (e.g., heating the substrate such that itreaches a threshold temperature during charging and/or discharging of anelectrochemical device comprising the article comprising the substrate).In some embodiments, a heat-induced change in volume of the substrate isan increase in volume of the substrate. For example, in someembodiments, the substrate has a positive thermal expansion coefficient(e.g., at the threshold temperature), and heating the substrate causes athermal expansion of the substrate. For example, in some embodiments,substrate 120 comprises a material having a positive thermal expansioncoefficient, and heating substrate 120 causes an increase in volume ofsubstrate 120. However, in some embodiments, a heat-induced change involume of the substrate is a decrease in the volume of the substrate.For example, in some cases the substrate has a negative thermalexpansion coefficient at the threshold temperature. For example,according to certain embodiments, substrate 120 comprises a materialhaving a negative thermal expansion coefficient (e.g., at a thresholdtemperature), and heating substrate 120 causes a decrease in volume ofsubstrate 120. In certain cases, the substrate comprises aheat-shrinkable film. In some cases, the substrate comprises a polymericmaterial such as polyvinyl alcohol.

In some embodiments, the article is configured such that, when thetemperature of the article reaches a threshold temperature, at least oneof the current collector bridges no longer couples the current collectorsegment associated with that current collector bridge to the currentcollector bus due, at least in part, to a heat-induced change in volumeof the substrate. Referring to FIG. 2A, when article 100 reaches acertain threshold temperature, current collector bridge 123 no longerelectronically couples the current collector segment 122 to currentcollector bus 121. Such a configuration may be useful in electronicallyisolating the discrete electrode segment. For example, in someembodiments, the article is configured such that, when the temperatureof the article reaches a threshold temperature, at least one of thediscrete electrode segments is no longer electronically coupled to thecurrent collector bus due, at least in part, to a heat-induced change involume of the substrate. Referring to FIG. 2B, in certain embodiments,electrode segment 130 a is electronically coupled to current collectorbus 121 via current collector segment 122 and current collector bridge123. In certain cases, when article 100 reaches (e.g., is heated to) athreshold temperature and current collector bridge 123 no longerelectronically couples the current collector segment 122 to currentcollector bus 121, no electronically conductive path exists for currentgenerated at discrete electrode 130 a to reach current collector bus121, thereby electronically isolating discrete electrode segment 130 a.

In some embodiments, the article is configured such that the thresholdtemperature referred to herein falls within a certain range oftemperatures. For example, the article may be configured such that thethreshold temperature is high enough that a loss of electronic couplingbetween the discrete electrode segment and the current collector bus(e.g., due to a change in volume of the substrate) does not occur duringnormal operation of an electrochemical device comprising the article(e.g., normal charging and/or discharging without short-circuiting orthermal runaway occurring). As such, the article may be configured incertain embodiments such that the threshold temperature of the articleis greater than or equal to 50° C., greater than or equal to 55° C.,greater than or equal to 60° C., greater than or equal to 70° C.,greater than or equal to 75° C., greater than or equal to 80° C.,greater than or equal to 85° C., greater than or equal to 90° C.,greater than or equal to 90° C., greater than or equal to 95° C.,greater than or equal to 100° C., or more. It should be understood thata threshold temperature of an article falling within a certain range oftemperatures means that the specific temperature at which the article isconfigured, upon a heat-induced change in volume of the substrate, toundergo at least one electronic decoupling as described herein (e.g.,between at least one discrete electrode segment and the currentcollector bus, between at least one discrete current collector segmentand the current collector bus) falls within that range. An articleconfigured to have a threshold temperature of 65° C. (e.g., an articlethat, when heated, will undergo at least one electronic decoupling asdescribed herein once the temperature of the article reaches 65° C. dueat least in part to a change in volume of the substrate) is one exampleof an article for which the threshold temperature is greater than orequal to 50° C., because 65° C. falls within the range of values greaterthan or equal to 50° C.

In some embodiments, the article may be configured such that thethreshold temperature is low enough that the loss of electronic couplingbetween the discrete electrode segment and the current collector busoccurs at a low enough temperature that significant damage to thearticle and/or an electrochemical device comprising the article does notoccur prior to the loss of coupling. As such, the article may beconfigured in certain embodiments such that the threshold temperature ofthe article is less than or equal to 150° C., less than or equal to 145°C., less than or equal to 140° C., less than or equal to 130° C., lessthan or equal to 120° C., or less. As another non-limiting example, anarticle configured to have a threshold temperature of 110° C. (e.g., anarticle that, when heated, will undergo at least one electronicdecoupling as described herein once the temperature of the articlereaches 110° C. due at least in part to a change in volume of thesubstrate) is an article for which the threshold temperature is lessthan or equal to 120° C., because 110° C. falls within the range ofvalues less than or equal to 120° C.

The threshold temperature for an article described herein may bemeasured, for example, by running a test current between the discreteelectrode segments and the current collector bus while ramping thetemperature of the article (or a component thereof). The thresholdtemperature would be determined by recording the temperature when a lossof electronic coupling (e.g., an interruption in the test current)between at least one of the discrete electrode segments and the currentcollector bus is observed.

One way in which the article may be configured to have at least one ofthe current collector bridges no longer couple the current collectorsegment associated with that current collector bridge to the currentcollector bus when the temperature of the article reaches a thresholdtemperature is by selecting materials for the current collector bridgeand the substrate that have different thermal expansion coefficients.Thermal expansion coefficients can be expressed in terms of linearthermal expansion coefficients (relating to fractional changes in thelength of the material in response to a change in temperature), arealthermal expansion coefficients (relating to fractional changes in thearea of the material in response to a change in temperature), and/orvolumetric thermal expansion coefficients (relating to fractionalchanges in the volume of the material in response to a change intemperature). Unless otherwise stated, thermal expansion coefficientsreferred to herein correspond to linear thermal expansion coefficients.In such a way, during a heating process, the volume of the substrate mayexpand (or contact) to a different degree than the current collectorbridge due to the differing thermal expansion coefficients, leading to asource of mechanical stress that could lead to a mechanical failure(e.g., fracturing or delamination) that results in a loss of electroniccoupling between the current collector segment and the current collectorbridge.

In some embodiments, the article is configured such that, when thetemperature of the article reaches a threshold temperature, at least oneof the current collector bridges undergoes ultimate tensile failure.Ultimate tensile failure of a material refers to a breaking (e.g.,fracturing) of the material due to the material experiencing tension.One non-limiting example of such configuration is that in which thethermal expansion coefficient of the substrate is greater than thethermal expansion coefficient of the at least one current collectorbridge. For example, referring to FIG. 2A, substrate 120 may be made outof a material having a greater thermal expansion coefficient than thatof the material that current collector bridge 123 is made out of, andcurrent collector bridge 123 may be attached to substrate 120 (e.g.,attached directly or via an intervening adhesive layer or domain),according to certain embodiments. When substrate 120 and currentcollector bridge 123 are heated (e.g., via a thermal load), substrate120 will expand to a greater degree than does current collector bridge123, resulting in current collector bridge 123 experiencing a tensileforce that depends on the degree of expansion of substrate 120. In somecases, substrate 120 may expand to such a degree that the tensile forceapplied to current collector bridge 123 is sufficient to cause ultimatetensile failure of current collector bridge 123. Without wishing to bebound by any particular theory, other design factors that may be used tocontrol the likelihood of a current collector bridge undergoingmechanical failure such as ultimate tensile failure upon a certainchange in volume of the substrate include, but are not limited to, thethickness of the current collector bridge, the elastic modulus of thecurrent collector bridge, and/or the area of the current collectorbridge.

In some embodiments, at least one of the current collector bridgesundergoes ultimate tensile failure in such a way that the currentcollector bridge no longer electronically couples the current collectorsegment associated with that current collector bridge to the currentcollector bus due, at least in part, to a heat-induced change in volumeof the substrate. FIG. 3 depicts a top down view of one example ofarticle 100 following ultimate tensile failure of current collectorbridge 123 caused, at least in part, by a heat-induced change in volumeof the substrate, as described above, according to certain embodiments.As can be seen in FIG. 3 , the ultimate tensile failure of currentcollector bridge 123 results in a fracture that leads to a completediscontinuity in current collector bridge 123, thereby disruptingelectronic coupling between the collector segment 122 and currentcollector bus 121, and consequently disrupting electronic couplingbetween discrete electrode segment 130 a and current collector bus 121.

In some embodiments, the article is configured such that, once thetemperature of the article reaches a threshold temperature, at least oneof the current collector bridges undergoes ultimate compressive failure(e.g., ultimate linear compressive failure). Ultimate compressivefailure of a material refers to a breaking (e.g., fracturing orbuckling) of the material due to the material experiencing compression.One non-limiting example of such configuration is that in which thethermal expansion coefficient of the substrate is less than the thermalexpansion coefficient of the at least one current collector bridge.Another non-limiting example of such configuration is that in which thethermal expansion coefficient of the substrate is negative (e.g., thesubstrate is a heat-shrinkable film). In some embodiments, the at leastone of the current collector bridges undergoes ultimate compressivefailure in such a way that the at least one of the current collectorbridges no longer electronically couples the current collector segmentassociated with that current collector bridge to the current collectorbus due, at least in part, to a heat-induced change in volume of thesubstrate.

In some embodiments, a first component of the article (e.g., a currentcollector bridge) and a second component of the article (e.g., thesubstrate) in direct contact and attached to the first component areconfigured such that the first component and second component have acertain thermal expansion differential. The thermal expansiondifferential, as used herein, is expressed as:

$\frac{\frac{\frac{A_{1}}{A_{2}}\sigma_{{ult},1}}{E_{2}} + \frac{\sigma_{{ult},1}}{E_{1}}}{\alpha_{2} - \alpha_{1}}$

where A₁ is the area of the first component, A₂ is the area of thesecond component, α₁ is the linear expansion coefficient of the firstcomponent, α₂ is the linear expansion coefficient of the secondcomponent, E₁ is the modulus of elasticity of the first component, E₂ isthe modulus of elasticity of the second component, and σ_(ult,1) is theultimate tensile strength of the first component. The thermal expansiondifferential depends on the materials selected for the first componentand/or the second component, as well as the respective areas of thefirst component and the second component. In some, but not necessarilyall embodiments, a temperature change, ΔT, of the first component of thearticle and/or a second component results in ultimate tensile failure ofthe first component if the temperature change is greater than or equalto the thermal expansion differential. In other words, in someembodiments, the first component of the article fails in tension (insome cases leading to a loss of electronic coupling between certaincomponents of the article) if the inequality expressed in Eq. 1 is met:

$\begin{matrix}{{\Delta T} \geq \frac{\frac{\frac{A_{1}}{A_{2}}\sigma_{{ult},1}}{E_{2}} + \frac{\sigma_{{ult},1}}{E_{1}}}{\alpha_{2} - \alpha_{1}}} & (1)\end{matrix}$

In embodiments in which Eq. 1 is satisfied, a change in temperature ofΔT will lead to ultimate tensile failure of the first component (e.g., acurrent collector bridge) if α₂ is greater than α₁. In some embodiments,Eq. 1 may be used to determine the temperature change necessary to causeultimate tensile failure of the first component if the geometry andmaterials selected for the first component and second component areknown.

In some embodiments, the first component (e.g., at least one currentcollector bridge) and/or the second component (e.g., the substrate) havea thermal expansion differential of greater than or equal to 10° C.,greater than or equal to 15° C., greater than or equal to 20° C.,greater than or equal to 25° C., greater than or equal to 30° C.,greater than or equal to 40° C., or more. In some embodiments, the firstcomponent (e.g., at least one current collector bridge) and/or thesecond component (e.g., the substrate) have a thermal expansiondifferential of less than or equal to 100° C., less than or equal to 90°C., less than or equal to 80° C., less than or equal to 70° C., lessthan or equal to 60° C., or less. Combinations of the above ranges arepossible. For example, in some embodiments, the first component (e.g.,at least one current collector bridge) and/or the second component(e.g., the substrate) have a thermal expansion differential of greaterthan or equal to 10° C. and less than or equal to 100° C.

In some embodiments, the article is configured such that, when thetemperature of the article reaches a threshold temperature, at least oneof the current collector bridges undergoes a change other than ultimatetensile failure or ultimate compressive failure such that the at leastone of the current collector bridges no longer electronically couplesthe current collector segment associated with that current collectorbridge to the current collector bus due, at least in part, to aheat-induced change in volume of the substrate. For example, in somecases, the change in volume of the substrate causes a delamination ofthe current collector bridge such that it loses contact with at leastone of either the current collector segment to which the currentcollector bridge is associated or the current collector bus.

In some embodiments, the heating of the article described herein(resulting in a heat-induced change in volume of the substrate) occurspassively. Heating of the article occurs passively if it occurs in theabsence of the application of a thermal load from a heater describedherein. For example the article may be heated passively due to a faultin an electrochemical device that comprises the article during chargingand/or discharging of the electrochemical device, such as whenshort-circuiting and/or thermal runaway occur (e.g., due to corrosion orfatigue of one or more parts of the electrochemical device). Suchprocesses may cause heating of one or more components of the article dueto resistive heating and/or the release of heat from exothermic chemicalreactions, in some cases raising the temperature above the thresholdtemperature.

In some embodiments, at least a portion of the heat-induced change involume of the substrate occurs due to an active heating process. Anactive heating process involves the application of a thermal load from aheater. As used herein, a heater is a component that can receive asignal (e.g., an electrical signal) that actuates the heater and causesit to apply a thermal load. In some cases, heating the substrate isaccomplished, at least in part, via the use of a heater that is part ofthe electrochemical device. In some embodiments, a heater is an externalcomponent adjacent to the article. However, in certain embodiments, theheater is a component integrated into the article (e.g., as a resistiveheater applied as a thin film to one or more layers of the article). Insome cases, if the substrate comprises a material with a sufficientelectronic conductivity, the substrate itself can serve as a heater.

In some embodiments, the article comprises a heater adjacent to thesubstrate. In certain cases, the article comprises multiple heatersadjacent to the substrate. As mentioned above, the heater may beconfigured to heat at least a portion of the article described herein.For example, FIG. 7A shows exemplary article 100 comprising heater 140adjacent to substrate 120, and, in some cases, heater 140 is capable ofheating article 100. It may be useful, in accordance with certain butnot necessarily all embodiments, to include a heater in an articledescribed herein for a variety of reasons. For example, the heater maybe used to heat the substrate such that a heat-induced change in volumeof the substrate occurs, resulting in a loss of electronic couplingbetween one or more discrete electrode segments and the currentcollector bus, as described above in relation to active heating of thearticle. In certain cases, including a heater adjacent to the article(e.g., the substrate) can provide a way to maintain a temperature of thearticle within a desired range, such as in cases in which the article ispart of an electrochemical device that may be desired to operate inlow-temperature ambient conditions (e.g., a battery for ofelectric-powered vehicle operating during winter). It should beunderstood that while, in some cases, the heater is immediately adjacentto the substrate (e.g., attached, coated, or vacuum deposited directlyon to the substrate with no intervening layers or structures between theheater and the substrate, as is illustrated in FIG. 7A and FIG. 7B), incertain cases, the heater is disposed directly on or more components(e.g., layers) of the article that are not the substrate. FIG. 7A showsa plurality of heaters 140, each next to (but not in direct contactwith) a discrete electrode segment and/or a discrete current collectorsegment, in accordance with certain embodiments. In some embodiments,the distance between the heater and the substrate is less than or equalto 5 mm, less than or equal to 3 mm, less than or equal to 2 mm, lessthan or equal to 1 mm, less than or equal to 0.5 mm, less than or equalto 0.2 mm, less than or equal to 0.1 mm, or less.

In some cases, the heater replaces (i.e., “takes the place of”) one ormore discrete electrode segments and/or components of the currentcollector domain in the article structure. For example, in cases inwhich discrete current collector segments are deposited at periodiclocations along the substrate during fabrication (e.g., via a skipcoating process), one or more of the locations may be masked such that acurrent collector segment is not deposited there, and, at a later step,a heater is placed at that one or more locations (e.g., following anunmasking step).

In some embodiments, the heater is located near one or more of the endsof the article. For example, in some cases, the heater is located withinthe final 20%, within the final 10%, or within the final 5% of thelength of the article. In some, but not necessarily all cases, nodiscrete electrode segments or current collector segments are locatedbetween the heater and an end of the substrate (referring to the endsaccording to a long axis of the substrate). For example, FIG. 7B shows anon-limiting embodiment in which heater 140 is positioned near the endof article 100, as opposed to an interior location such as is shown inthe illustration of FIG. 7A. Placing the heater at or near one of theends of the article may assist with ease of fabrication (e.g., bypotentially avoiding complicated masking steps) and allow for easyaccess to the heater even when the article is folded, in accordance withcertain, but not necessarily all embodiments. However, in certain cases,placing the heater in an interior location, such as is shown in FIG. 7A,may be useful in providing more uniform heat throughout the article,such as in cases in which the article is folded, as well as allowing forlocalized heating (e.g., near regions of the substrate near particularcurrent collector bridges in accordance with certain, but notnecessarily all embodiments). As mentioned above in described in moredetail below, in some cases, the article is foldable. In some suchcases, the heater is positioned between folded sections of the articlewhen the article is folded. Such a configuration may, in certainembodiments, allow for the heater to easily heat interior portions(e.g., folds) of the article and/or a folded electrochemical devicecomprising the article.

In some embodiments, the heater comprises a thin film. In certain, butnot necessarily all cases, the heater is a thin film. For example,referring to FIG. 7A, heater 140 is a thin film, in accordance withcertain embodiments. In embodiments in which the heater is or comprisesa thin film, the thin film may be deposited (e.g., by physical orchemical vacuum deposition techniques, spin coating, or other suitablethin film deposition techniques described herein) on to a portion of thearticle. For example, in some cases, the heater is a thin film depositeddirectly on to the substrate (e.g., during the manufacturing of thesubstrate). In certain cases however, the thin film of the heater isdeposited on to one or more other components of the article. In certaincases, a plurality of heaters comprising thin films are positioned onthe article as a plurality of discrete thin film segments (e.g., thinfilm segments deposited via skip coating or coating with a mask). Theuse of heaters comprising thin films may be beneficial in cases in whicha relatively high volumetric energy density of a battery comprising thearticle is desired, in accordance with some, but not necessarily allembodiments. Additionally, thin film heaters may be useful inintegrating the heater into an article that is foldable, because thethin films may be thin enough to avoid obstructing the folding of thearticle, according to certain embodiments. In some cases, the thickness(e.g., average thickness) of the heater (e.g., a thin film heater) isless than or equal to 1 mm, less than or equal to 500 μm, less than orequal to 200 μm, less or equal to 100 μm, less than or equal to 50 μm,less than or equal to 20 μm, less than or equal to 10 μm, less than orequal to 5 μm, less than or equal to 2 μm, less than or equal to 1 μm,less than or equal to 0.5 μm, less than or equal to 200 nm, or less. Incertain cases, the heater has a thickness of greater than or equal to 20nm, greater than or equal to 50 nm, greater than or equal to 100 nm, ormore.

In some cases, the heater comprises a material capable of performingresistive heating. For example, the heater may be electronically coupledto an external electrical circuit (e.g., via power leads) such that,when current is passed through the electrical circuit, the resistance ofthe heater causes resistive heating (i.e., joule heating) to occur. Theheat generated by such resistive heating can, in some cases, heat thearticle and/or an electrochemical device comprising the article. Incertain cases, the heater comprises a metal or metal alloy. For example,the heater may comprise a resistive metal or metal alloy (e.g., metalsor metal alloys having relatively high resistivities), in order topromote resistive heating, in accordance with certain embodiments.Examples of materials that the heater may comprise include, but are notlimited to, nickel alloys (such as nichrome, Constantan, Evanohm, etc.),stainless steel, graphite, silicon-based compounds, combinationsthereof, and the like. Generally, the material for the heater (e.g., aheater comprising a thin film) can be selected based on one or moreproperties, including the resistivity of the material, as explained inmore detail below.

In some embodiments, the heater comprises a conductive wire. Forexample, in FIG. 7A or 7B, heater 140 is a conductive wire, rather thana thin film, in accordance with some, but not necessarily allembodiments. The conductive wire may be deposited onto the article(e.g., immediately adjacent to the substrate, or on an interveninglayer) to form a conductive track on the article. As in the case of theheater comprising a thin film, a heater comprising a conductive trackmay be formed, in some cases, using a patterned mask on the substrate ora layer on the substrate. In some cases, the conductive wire of theheater is electronically coupled to an external circuit, as is describedabove for the heaters comprising thin films, such that electricalcurrent may be passed through the conductive wire, thereby causingresistive heating. The conductive wire of the heater may form any numberof patterns or paths along the article, depending on the desired area ofheating from the heater. For example, in some cases, the conductive wireis relatively straight along areas of the article where substantialheating may not be desired, but forms, for example, a serpentine patternnear areas that are desired to be substantially heated (e.g., nearcurrent collector bridges in some cases in which the heater is used toactively cause a heat-induced change in volume of the substrate).

In embodiments in which the heater comprises a conductive wire, theheater may comprise any of a number of suitable materials havingsufficient resistivity to cause a desired heating of the article. Forexample, in some cases, the heater comprising a conductive wirecomprises a metal and/or metal alloy. As described above for heaterscomprising thin films, the conductive wire may comprise a resistivemetal or resistive metal alloy. Examples of the material for theconductive wire of the heater include, but are not limited to, nickelalloys (such as nichrome, Constantan, Evanohm, etc.), stainless steel,graphite, silicon-based compounds, combinations thereof, and the like.As mentioned above, the material for the heater comprising a conductivewire may be selected in order to achieve a desired resistance for theheater.

The resistance of a heater (e.g., a heater comprising a thin film or aheater comprising a conductive wire) can, in some cases, be determinedusing Eq. 2:

$\begin{matrix}{R = \frac{\rho L}{A}} & (2)\end{matrix}$

where R is the resistance of the heater, ρ is the resistivity of thematerial of which the heater is made, L is the length of the heater inthe direction of electrical current flow through the heater, and A isthe cross-sectional area of the heater through which electrical currentflows. As can be seen from Eq. 2, the desired resistance of the heatermay, in some cases, be achieved by selecting materials based on theirresistivity, p, with materials having greater resistivity leading togreater resistances. Additionally, the geometry of the heater may bechosen in order to determine the resistance of the heater. For example,as can be seen from Eq. 2, heaters with greater length dimensions havegreater resistance (e.g., longer conductive wires, greater lengthdimensions of thin films in the direction of current flow (e.g., betweentwo power leads)). The cross-sectional area, A, through which currentflows in the heater is inversely related to the resistance, according toembodiments that satisfy Eq. 2. As such, the resistance of the heatermay be increased by using thinner conductive wires (e.g., wires withsmall diameters or cross-sectional dimensions), in embodiments in whichthe heater comprises conductive wires. In some cases in which the heateris or comprises a thin film, the resistance can be expressed using Eq.3:

$\begin{matrix}{R = \frac{\rho L}{tw}} & (3)\end{matrix}$

where t is the thickness of the thin film and w is the width of the thinfilm in a direction perpendicular to the direction of current flow(e.g., perpendicular to the length dimension). As such, the geometry ofthe thin films, including the thicknesses and width of the thin films,can be adjusted during fabrication of the article (e.g., by varying thewidth of the thin film or by adjusting the thickness of the thin films)in order to adjust the resistance of the heater, in accordance withcertain embodiments.

The resistance of the heater may be important in cases in whichresistive heating (e.g., joule heating) is used as at least one of themechanisms of heating. The heat produced during resistive heating, asmeasured in terms of power, is generally proportional to the square ofthe electrical current and linearly proportional to the resistance.Therefore, heaters having a greater resistance will provide greaterheating for a given electrical current passed through the heater,according to certain embodiments. In some embodiments, the heater has arelatively high resistance. For example, in some cases, the heater hasan electrical resistance of greater than or equal to 50Ω, greater thanor equal to 60Ω, greater than or equal to 75Ω, greater than or equal to100Ω, greater than or equal to 125Ω, greater than or equal to 150Ω,greater than or equal to 200Ω, and/or up to 300Ω, up to 400Ω, up to500Ω, up to 1,000Ω, or more, at room temperature (23° C.). Combinationsof the above ranges are possible. For example, in some cases, the heaterhas an electrical resistance of greater than or equal to 50Ω and lessthan or equal to 1000Ω.

In some embodiments, the heater is electronically isolated from (e.g.,not electronically coupled to) certain other components of the articleand/or components of an electrochemical device comprising the article.For example, in some cases, the heater is not electronically coupled tothe plurality of discrete electrode segments. Having the heater beelectronically isolated from the discrete electrode segments may preventcurrent being passed through the heater from electronically interferingwith the electrochemical operation of an electrochemical devicecomprising the article during charging and/or discharging and,similarly, prevent current being passed through the heater fromelectronically interfering with electrochemical operation of theelectrochemical device. In some embodiments, the heater is notelectronically coupled to the current collector domain. Having heaternot be electronic the coupled to the current collector domain (e.g.,current collector domain 121) may also avoid interference with theoperation and performance of an electrochemical device comprising thearticle, according to certain embodiments.

The heater may be prevented from being electronically coupled to theplurality of discrete electrode segments and/or the current collectordomain of the article via a variety of methods. For example, the heatermay be placed at the end of the article and physically separated fromthe discrete electrode segments and the current collector domain as isshown in FIG. 7B. In some embodiments (e.g., in embodiments in which theheater is integrated into the interior of the article, as is shown inFIG. 7A), the heater may be prevented from being electronically coupledto the discrete electrode segments and/or the current collector domainby incorporating one or more intervening layers between the heater andthe discrete electrode segments and/or the current collector domain. Insome embodiments, at least a portion of the heater is coated with anelectrically insulating material. For example, the heater may be coatedwith an electrically insulating polymer coating over some or all of theheater such that it is not in direct contact with the current collectordomain or the discrete electrode segments. In some cases, a coating(e.g., a protective polymer coating) is applied to the heater (e.g., athin film heater or a heater comprising a conductive wire) such that theheater is physically isolated from the electrolyte in cases in which thearticle is incorporated into an electrochemical device.

In some cases, the heater is electrically coupled to an externalcircuit. For example, the heater may be coupled to an external circuit(e.g., via power leads in contact with the heater) corresponding to abattery control system and management circuitry, in accordance withcertain embodiments. The battery control system may, upon receivingcertain signals or readings of the battery conditions (e.g.,temperature, current, pressure, etc.), initiate the application ofcurrent (e.g., by applying a voltage) to the heater, thereby causing theheater to heat at least a portion of the article, in accordance withcertain embodiments. In some cases, the heater is configured to beactuated by one or more sensors, described in more detail below. Forexample, the heater may be electronically coupled to a battery controlsystem and management circuitry that is configured to receive signalsfrom one or more sensors that are adjacent to the substrate of thearticle. The one or more sensors may be configured to send a signal tothe battery control system (e.g., when a temperature is above atemperature threshold or a pressure is below a pressure threshold),which, in turn, may send a signal to that actuates the heater to causeit to start, stop, or adjust its heating.

In some embodiments, the article described herein comprises one or moresensors. In certain cases, the one or more sensors is adjacent to thesubstrate of the article. Incorporation of sensors into the article maybe useful for monitoring the status or the performance of the article,such as in cases in which the article is part of an electrochemicaldevice (e.g., a battery), according to certain embodiments. The one ormore sensors may, at least in part, allow for detecting a condition(e.g., temperature, pressure) of an electrochemical device. In somecases, the one or more sensors adjacent to the substrate is configuredto respond to a condition of the article. FIG. 8A depicts exemplaryarticle 100 comprising sensor 160 configured to respond to a condition(e.g., temperature, pressure) of article 100. It should be understoodthat while, in some cases, the one or more sensors is immediatelyadjacent to the substrate (e.g., attached, coated, or vacuum depositeddirectly on to the substrate with no intervening layers or structuresbetween the one or more sensors and the substrate, as is illustrated inFIG. 8A and FIG. 8B), in certain cases, the sensor is disposed directlyon or more components (e.g., layers) of the article that are not thesubstrate. FIG. 8A shows a plurality of sensors 160, each next to (butnot in direct contact with) a discrete electrode segment and/or adiscrete current collector segment, in accordance with certainembodiments. In some embodiments, the distance between the heater andthe substrate is less than or equal to 5 mm, less than or equal to 3 mm,less than or equal to 2 mm, less than or equal to 1 mm, less than orequal to 0.5 mm, less than or equal to 0.2 mm, less than or equal to 0.1mm, or less.

As in the case of the heater described above, in some cases, the one ormore sensors replaces (i.e., “takes the place of”) one or more discreteelectrode segments and/or components of the current collector domain inthe article structure. For example, in cases in which discrete currentcollector segments are deposited at periodic locations along thesubstrate during fabrication (e.g., via a skip coating process), one ormore of the locations may be masked such that a current collectorsegment is not deposited there, and, at a later step, a sensor is placedat that one or more locations (e.g., following an unmasking step).

In some embodiments, the one or more sensors is located near one or moreof the ends of the article. For example, in some, but not necessarilyall cases, no discrete electrode segments or current collector segmentsare located between the one or more sensors and an end of the substrate(referring to the ends according to a long axis of the substrate). Forexample, FIG. 8B shows a non-limiting embodiment in which sensor 160 ispositioned near the end of article 100, as opposed to an interiorlocation such as is shown in the illustration of FIG. 8A. Placing thesensor at or near one of the ends of the article may assist with ease offabrication (e.g., by potentially avoiding complicated masking steps)and allow for easy access to the sensor even when the article is folded,in accordance with certain, but not necessarily all embodiments.However, in certain cases, placing the one or more sensors in aninterior location, such as is shown in FIG. 8A, may be useful indetecting and providing localized information about the condition of thearticle (e.g., the temperature or pressure experienced by individualdiscrete electrode segments). As mentioned above and described in moredetail below, in some cases, the article is foldable in someembodiments. In some such cases, the one or more sensors is positionedbetween folded sections of the article when the article is folded. Sucha configuration may, in certain embodiments, allow for the one or moresensors to easily respond to conditions of interior portions (e.g.,folds) of the article and/or a folded electrochemical device comprisingthe article.

In some embodiments, at least one of the one or more sensors is atemperature sensor configured to respond to a temperature of thearticle. For example, FIG. 8A depicts sensor 160 adjacent to substrate120 of article 100, according to certain embodiments. In some cases, thetemperature sensor is capable of measuring the temperature of at least aportion of the article. In certain cases, the temperature sensorresponds (e.g., by sending an electrical signal) that varies based onthe temperature at the sensor. In certain cases, the temperature sensorresponds when a temperature above or below certain pre-determinedtemperatures are detected. Incorporation of temperature sensors in thearticle or an electrochemical device comprising the article may, inaccordance with certain but not necessarily all embodiments, allow forthe detecting and/or monitoring of the temperature of substantially theentire article or, in some cases, the temperature near individualdiscrete electrode segments.

The temperature sensor can be any of a number of suitable types oftemperature sensor. In some cases, the temperature sensor is orcomprises a thermocouple. In certain cases, the temperature sensor is orcomprises a thermistor. In some embodiments, the temperature sensor isor comprises a resistance temperature detector (RTD). A thermocouple ora thermistor may be, for example, commercially acquired and incorporatedinto the article, or the thermocouple may be fabricated incorporatedinto the article during the manufacturing of the article itself. Insome, but not necessarily all embodiments, the temperature sensor is orcomprises a thin film. In embodiments in which the temperature sensor(e.g., thermocouple, thermistor, RTD) is fabricated during themanufacture of the article, the temperature sensor may be formed on aportion of the article (e.g., the substrate or one or more other layers)by any number suitable methods, such as vacuum deposition methods (e.g.,sputtering, evaporation). The temperature sensor may comprise a materialhaving a known resistance versus temperature profile. Examples ofmaterials the temperature sensor may comprise include, but are notlimited to, platinum, nickel, copper, iron, or combinations thereof. Inone non-limiting example, the temperature sensor is an RTD comprising anelectrically non-conductive layer (e.g., a ceramic layer) on which amaterial having a known resistance versus temperature profile (e.g.,platinum, nickel, copper, iron) is deposited (e.g., in a serpentinepattern). The material having a known resistance versus temperatureprofile may be electronically coupled to an external circuit (e.g., acomputer system and/or a battery control system).

In some embodiments, at least one of the one or more sensors is apressure sensor. For example, referring again to FIG. 8A, sensor 160 isa pressure sensor, in accordance with certain embodiments. The pressuresensor may be configured to respond to a pressure experienced by thearticle. In some cases, the pressure sensor is capable of measuring thepressure or force experienced by at least a portion of the article. Incertain cases, the pressure sensor responds (e.g., by sending anelectrical signal) that varies based on the pressure at the sensor. Incertain cases, the pressure sensor responds when a pressure above orbelow certain pre-determined pressures is detected. Detecting thepressure experienced by the article or a portion thereof may be usefulfor detecting problems in an electrochemical device comprising thearticle (e.g., during cycling of a battery stack) or determining a riskfor damage of the electrochemical device (e.g., in cases in whichexcessive forces being applied to the electrochemical device), inaccordance with some, but not necessarily all embodiments.

The pressure sensor can be any of a variety of type of suitable pressuresensors. In some cases, the pressure sensor is a capacitance-basedpressure sensor. One example of a capacitance-based pressure sensor isone comprising two electrodes with an electrically insulative materialpositioned between the two electrodes. The electrically insulativematerial may have a known dielectric constant. In certain cases, theelectrically insulative material is configured such that the forceapplied to the capacitive-based sensor comprising the two electrodes inthe electrically insulative material causes the thickness of theelectrically insulative material to change, thereby varying a measuredcapacitance between the two electrodes. For example, in some cases, theelectrically insulative material positioned between the two electrodesis a polymeric material. The polymeric material may be relatively softand have a known dielectric constant. In some cases, the pressure sensoris or comprises a strain gauge. In certain embodiments, the pressuresensor comprises a piezoelectric or piezoresistive sensor. Such sensorstypically comprises piezoelectric or piezoresistive materials coupled toan external electrical circuit capable of detecting and measuring changein electric charge or resistance upon mechanical deformation of thematerials. In certain embodiments, the pressure sensor is or comprises athin film. Non-limiting examples of pressure sensors (e.g., in thin filmform) are described in F. Schmaljohann, D. Hagedorn, and F. Löffler.“Thin Film Sensors for measuring small forces.” Journal of Sensors andSensor Systems. No. 4, (February 2015), 91-95. In some cases, thepressure sensor is commercially available and attached or coupled to thearticle or an electrochemical device comprising the article. However, insome cases, the pressure sensor (e.g., a thin film pressure sensor) isfabricated during the manufacture of the article. In some such cases,the pressure sensor is formed by vacuum deposition, coating and curing(e.g., in the case of polymeric materials), printing (e.g., inkjetprinting, screen-printing), and/or by spray methods (e.g., aerosol spraymethods).

In some embodiments, the one or more sensors is electronically isolatedfrom (i.e., not electronically coupled to) certain other components ofthe article and/or components of an electrochemical device comprisingthe article. For example, in some cases, the one or more sensors is notelectronically coupled to the plurality of discrete electrode segments.Having the one or more sensors be electronically isolated from thediscrete electrode segments may prevent current being passed through theone or more sensors from interfering with the operation of anelectrochemical device comprising the article during charging and/ordischarging and, similarly, prevent current being passed through theheater from interfering with operation of the electrochemical device. Insome embodiments, the one or more sensors is not electronically coupledto the current collector domain. Having the one or more sensors not beelectronically coupled to the current collector domain (e.g., currentcollector domain 121) may also avoid interference with the operation andperformance of an electrochemical device comprising the article,according to certain embodiments.

The one or more sensors may be prevented from being electronicallycoupled to the plurality of discrete electrode segments and/or thecurrent collector domain of the article via a variety of methods. Forexample, the one or more sensors may be placed at the end of the articleand physically separated from the discrete electrode segments and thecurrent collector domain as is shown in FIG. 8B. In some embodiments(e.g., in some embodiments in which the one or more sensors isintegrated into the interior of the article, as is shown in FIG. 8A),the heater may be prevented from being electronically coupled to thediscrete electrode segments and/or the current collector domain byincorporating one or more intervening layers between the one or moresensors and the discrete electrode segments and/or the current collectordomain. In some embodiments, at least a portion of the one or moresensors is coated with an electrically insulating material. For example,the one or more sensors may be coated with an electrically insulatingpolymer coating over some or all of the one or more sensors such that itis not in direct contact with the current collector domain or thediscrete electrode segments. In some cases, a coating (e.g., aprotective polymer coating) is applied to the one or more sensors (e.g.,a thin film temperature sensor or pressure sensor) such that the one ormore sensors is physically isolated from the electrolyte in cases inwhich the article is incorporated into an electrochemical device.

In some cases, the one or more sensors is electronically coupled to anexternal circuit. For example, the one or more sensors may be coupled toan external circuit (e.g., via power leads in contact with the sensor)corresponding to a battery control system and management circuitry, inaccordance with certain embodiments. The battery control system may,upon receiving certain signals or readings of the battery conditions(e.g., from the one or more sensors), initiate the application ofcurrent (e.g., by applying a voltage) to a heater described herein,thereby causing the heater to heat at least a portion of the article, inaccordance with certain embodiments. Heating at least a portion of anelectrochemical device using a heater that is a part of theelectrochemical device due, at least in part, to a signal received inresponse to one or more sensors that are a part of the electrochemicaldevice may allow for rapid electronic isolation of problematic discreteelectrode segments (e.g., via a heat-induced volume change of thesubstrate), in accordance with certain, but not necessarily allembodiments. As another non-limiting example, the battery control systemmay receive a signal from a pressure sensor indicating that an appliedpressure/force to the electrochemical device is below a threshold valueand, upon receiving the signal, send a signal to a pressure applicatorto increase the applied pressure.

In some embodiments, the sensor may interact with one or moreprocessors, for example, to carry out any of the control schemesdescribed herein. In some embodiments, one or more processors may beused to process a signal from a sensor, for example, to carry out any ofthe control schemes described herein. In some embodiments, the batterycontrol system and/or management circuitry can comprises one or moreprocessors. Examples of suitable processors are described in more detailbelow.

In some embodiments, the thickness of the current collector bus isgreater than the thickness of at least one of the current collectorbridges. For example, as shown in FIG. 2B, current collector bus 121 hasa thickness dimension illustrated by thickness 161, while currentcollector bridge 123 has a thickness dimension illustrated by thickness162. In accordance with certain embodiments, thickness 161 is greaterthan thickness 162. Having the current collector bridge have a greaterthickness than that of at least one current collector bridge may allow,in certain cases, for the current collector bridge to be moremechanically robust (e.g., a greater applied force is required to causefailure) than the at least one current collector bridge. For example, incertain cases, changing the volume of the substrate causes both thecurrent collector bus and the at least one current collector bridge toexperience mechanical stress (e.g., tension, bending). In some cases,the mechanical stress results in the current collector bridge fracturing(e.g., due to ultimate tensile failure) but the current collector busnot fracturing, due to the greater thickness of the current collectorbus. Such a scenario may allow for discrete electrode segments coupledto the current collector bus via the at least one current collectorbridge to be electronically isolated upon a change in volume of thesubstrate without the current collector bus itself failing. In some suchcases, an electrochemical device comprising such an article can still becharged and/or discharged after the loss of the electronic couplingbetween the at least one of the electrode segments and the currentcollector bus. Additionally, having a relatively large thickness of thecurrent collector bus may allow for a decreased electrical resistanceand an increased current-carrying capability for the overall currentcollector domain.

In some embodiments, the current collector bus has a thickness that isat least three times, at least four times, at least 5 times, at least 8times, at least 10 times, at least 20 times, and/or up to 50 times, upto 75 times, or up to 100 times greater than the thickness of at leastone of the current collector bridges.

In some embodiments, one or more components of the current collectordomain are part of a unitary structure. For example, in someembodiments, the current collector bus and the plurality of currentcollector segments are part of a unitary structure. Two or morecomponents are part of a unitary structure if the component are formedof the same material or a consistent combination of materials (e.g., asingle metal alloy) and without breaks. In other words, a unitarystructure is a single piece made of a single material or a consistentcombination of materials, as opposed to multiple pieces in contact witheach other. For example, referring to FIG. 2A, in certain embodiments,current collector bus 121 and the plurality of current collectorsegments that include current collector segment 122 are part of aunitary structure. In some cases, the entire current collector domainforms a unitary structure. Referring to FIGS. 2A and 2B, while currentcollector bus 121, current collector segment 122, and current collectorbridge 123 associated with current collector segment 122 are illustratedas three separate components, in certain embodiments, collector bus 121,current collector segment 122 and current collector bridge 123 form aunitary structure (e.g., a unitary structure of copper metal or copperalloy). In some cases, each current collector segment and a currentcollector bridge associated with the current collector segment are partof a unitary structure. Forming one or more component of the currentcollector domain, such as the current collector bus, the plurality ofcurrent collector segments, and the current collector bridges associatedwith the current collector segments, as a unitary structure may simplifyfabrication of the article. For example, having the current collectorbus and the plurality of current collector segments be part of a unitarystructure may eliminate certain fabrication steps (e.g., by allowing forsimultaneous fabrication of the current collector bridges and thecurrent collector segments).

In some embodiments, the article is configured such that, above athreshold current (e.g., either an electrical discharge current or anelectrical charging current passing through the current collectordomain), at least one of the current collector bridges is mechanicallydeformed. The mechanical deformation may, in certain cases be caused bythe current collector bridge melting (e.g., resistive heating). Incertain cases, the current collector bridge is mechanically deformed dueto thermal shock caused by the electrical current reaching the thresholdcurrent. In some embodiments, the at least one current collector bridgeis mechanically deformed such that a current collector segmentelectronically coupled to that current collector bridge is no longerelectronically coupled to the current collector bus. Such a situationmay occur, in accordance with certain embodiments, when the currentcollector bridge is configured to “blow out” due to excessive current(i.e., current above a threshold current) such that the flow path ofcurrent along the current collector bridge is interrupted.

The threshold current referred to herein is the electrical current that,when reached (e.g., due to short circuiting), causes the mechanicaldeformation of the at least one current collector bridge such that acurrent collector segment associated to that current collector bridgebecomes decoupled from the current collector bus. In some embodiments,the article is configured such that the threshold current referred toherein falls within a certain range of currents. For example, thearticle may be configured such that the threshold current is high enoughthat a loss of electronic coupling between the current collector bridgeand the current collector bus (e.g., due to the mechanical deformation)does not occur during normal operation of an electrochemical devicecomprising the article (e.g., normal charging and/or discharging withoutshort-circuiting or thermal runaway occurring). As such, the article maybe configured in certain embodiments such that the threshold current ofthe article is greater than or equal to 10 A. It should be understoodthat a threshold current of an article falling within a certain range ofcurrents means that the specific current at which the article isconfigured, upon a mechanical deformation of at least one currentcollector bridge, to undergo at least one electronic decoupling asdescribed herein, falls within that range. An article configured to havea threshold current of 100 A is one example of an article for which thethreshold current is greater than or equal to 10 A, because 100 A fallswithin the range of values greater than or equal to 10 A.

In some embodiments, the article may be configured such that thethreshold current is low enough that the loss of electronic couplingbetween the current collector segment and the current collector busoccurs at a low enough current that significant damage to the articleand/or an electrochemical device comprising the article does not occurprior to the loss of coupling. As such, the article may be configured incertain embodiments such that the threshold current of the article isless than or 120 A. As another non-limiting example, an articleconfigured to have a threshold current of 90 A is an article for whichthe threshold current is less than or equal to 120 A, because 90 A fallswithin the range of values less than or equal to 120 A.

In some embodiments, one or more components of the articles and systemsdescribed herein are continuous structures. “Continuous,” as used todescribe a relationship between two sections, layers, or portions of astructure, means that there exists at least one pathway from the firstsection, layer, or portion to the second section, layer, or portion thatpasses only through the structure. E.g., a continuous sheet of material,folded upon itself or folded around a different material, can define twoor more sections or portions that remain part of the continuous sheet,because there exists at least one pathway from the first section to thesecond section that passes only through the sheet (e.g., a pathway thattravels from the first section along and around the fold, and to thesecond section). Referring to FIGS. 10A-10B, first anode portion 431,second anode portion 432, and folded anode region 435 of electrochemicaldevice 400B are sections of a structure (e.g., anode), and thatstructure is continuous with respect to first anode portion 431 andsecond anode portion 432 because there exists a pathway from first anodeportion 431, through folded anode region 435, and to second anodeportion 432 that passes only through the structure that includes firstanode portion 431, second anode portion 432, and folded anode region435. In contrast, referring to FIGS. 9A-9B, first anode portion 431 andsecond anode portion 432 of electrochemical device 400A are notcontinuous, because any pathway from first anode portion 431 to secondanode portion 432 must pass through at least one structure (e.g.,separator 450, first cathode portion 531, gap 405) that does not includefirst anode portion 431 and second anode portion 432.

In some embodiments, the current collector bus is a continuous layer.For example, referring to FIG. 1 , current collector bus 121 is acontinuous layer, as opposed to being formed of a plurality of discretelayers or sections. Having a continuous current collector bus may beuseful for a variety of reasons. For example, loss of an electricalconnection between the current collector bus and a component of anexternal circuit (e.g., an electrode tab) at one section of the currentcollector bus (e.g., due to a failure) does not necessarily disruptelectronic coupling between the current collector bus at that sectionand other components of the external circuit that form electricalconnections at other sections of the current collector bus, due to thecontinuous conductive path. For example, referring to FIG. 1 , anelectrical connection to external components such as electrode tabs aremade at section 203 and section 205 of current collector bus 121,according to certain embodiments. Electrical current generated atdiscrete electrode segment 130 a may be transferred to externalcomponents either at section 203 or section 205 of current collector bus121. Because current collector bus 121 is continuous, a loss ofelectrical connection between current collector bus 121 and an externalcomponent at section 203 does not prevent transfer of electrical currentgenerated at discrete electrode segment 130 a to the external circuit,because discrete electrode segment 130 a is still electrically coupledto current collector bus 121 at section 205.

Other components of the articles and systems described herein can alsobe continuous, as mentioned above. For example, the substrate of thearticle may be continuous. Referring to FIG. 1 , any two sections ofsubstrate 120 are continuous, according to certain embodiments. Having acontinuous substrate can allow for simplified fabrication of the articledescribed herein as well as of multi-cell batteries. For example, whenthe substrate is continuous, the article described herein can befabricated by attaching (e.g., via coating or deposition) the currentcollector domain and the plurality of discrete electrode segments onto asingle continuous substrate, rather than having to individuallymanufacture discrete electrode segments, substrate segments, and/orcomponents of the current collector domain and then attaching them(e.g., to form the article or a battery stack). Other components of thesystems described herein that may be continuous include, but are notlimited to, a separator and/or a second electrode of an electrochemicaldevice that comprises the article, as described in more detail below.

The article described herein may be fabricated according to any suitablemethod. In some cases in which the substrate is continuous, the currentcollector domain and/or the discrete electrodes are formed on thesubstrate. Non-limiting examples of techniques that can be used to formthe current collector domain (including the current collector bus andthe optional current collector segments and current collector bridges)as well as the plurality of discrete electrode segments include coatingand deposition methods such casting, evaporative deposition, vacuumdeposition, or spin-coating. One non-limiting example of a suitablevacuum deposition is sputtering.

One illustrative but non-limiting method of forming the article involvesstarting with a substrate comprising a release layer comprising asuitable material (e.g., polyvinyl alcohol). A mask can then patternedonto the substrate such that when a thin layer of metal (e.g., copper)is coated on to the substrate, regions (i.e., voids/gaps) of thesubstrate are not coated directly with the metal. Following the coatingof the metal to form at least a part of the current collector domain, anelectrode active material (e.g., lithium and/or lithium alloy) can becoated or deposited onto the metal layer (e.g., on the regions of themetal layer corresponding to current collector segments). Subsequentrelease of the substrate from the mask material results in the articledescribed herein, according to certain embodiments. In some cases, thepatterning of the mask on the substrate is designed such that regions ofthe coated metal correspond to current collector bridges, and in certaincases, the metal (e.g., copper metal) is deposited continuously and witha greater thickness at the edge of the article in order to create acurrent collector bus with an increased thickness relative to othercomponents of the current collector domain.

The use of a continuous substrate and/or a continuous current collectorbus when manufacturing a multi-cell battery can avoid the laborioussteps associated with fabricating batteries having stacked arrangements,resulting in a faster, easier, and less expensive manufacturing process.For example, having a continuous substrate (e.g., a release layer) uponwhich other components of the article (e.g., the current collectordomain and the plurality of discrete electrode segments) can bedeposited or coated obviates the need for cutting out separate laminatecells, arranging them, and making numerous external electrical contacts.

In some embodiments, the article may be folded. It may be particularlyuseful to fold the article when one or more components (e.g., thesubstrate, the current collector bus) are continuous. FIG. 2C shows aside view schematic of unfolded article 100 comprising continuoussubstrate 120 (e.g., prior to folding). FIG. 5 shows a side viewschematic of article 100 that is partially folded (with full foldinginvolving folding according to the two block arrows shown in FIG. 5 ),in accordance with certain embodiments. It should be noted that currentcollector bus 121 is omitted from article 100 in FIG. 5 for clarity.Folding the article may involve folding the substrate at the voids/gapsbetween discrete electrode segments and/or current collector segments.Referring again to FIG. 5 , substrate 120 is folded at the voids betweeneach current collector segment of the plurality of current collectorsegments that includes current collector segment 122. In folding thearticle in such a way, “double-sided” electrodes are formed, with eachside of the double-sided electrode comprising a discrete electrodesegment (e.g., a discrete electrode segment from the plurality ofdiscrete electrode segments 130). The use of double-side electrodes mayprovide for a battery with a relatively high volumetric energy density,which can be desirable in a number of applications.

In another aspect, electrochemical devices are described. In someembodiments, an electrochemical device comprises at least one anode andat least one cathode. It should be understood that although the articledescribed above comprising a current collector bus and a plurality ofdiscrete electrode segments may be included in the foldedelectrochemical device, other electrode geometries and configurationsmay be used in the folded electrochemical device. In certain cases, theelectrochemical device comprises a separator (e.g., a continuous orserpentine separator). The electrochemical device may be useful, in somecases, as a battery (e.g., a multi-cell battery such as a rechargeablelithium battery). As mentioned above, in some cases, the electrochemicaldevice is folded. In some, but not necessarily all cases, a foldedelectrochemical cell is easier and/or more economical to produce, and iscapable of having a relatively high volumetric energy density, whencompared to electrochemical devices formed with a stacked design ratherthan a folded design.

In some embodiments, the electrochemical device comprises multipleelectrode portions. For example, in some embodiments, theelectrochemical device comprises a plurality of anode portions. Eachanode portion of the electrochemical device may comprise an anode activesurface portion. In some cases, the electrochemical device comprises afirst anode portion comprising a first anode active surface portion, asecond anode portion comprising a second anode active surface portion, athird anode portion comprising a third anode active surface portion, anda fourth anode portion comprising a fourth anode active surface portion.In certain embodiments, each of the first anode portion, the secondanode portion, the third anode portion, and the fourth anode portioncomprise lithium and/or a lithium alloy as an anode active material.

In some embodiments, at least some of the anode portions of theelectrochemical device are discrete (e.g., discrete electrodes). Forexample, in some instances, each of the first anode portion, the secondanode portion, the third anode portion, and the fourth anode portion arediscrete. Referring to FIG. 9A, which shows a schematic cross-sectionalview of a partially unfolded electrochemical device for clarity,electrochemical device 400A comprises first anode portion 431 comprisingfirst anode active surface portion 441, second anode portion 432comprising second anode active surface portion 442, third anode portion433 comprising third anode active surface portion 443, and fourth anodeportion 434 comprising fourth anode active surface portion 444. Inaccordance with certain embodiments of electrochemical device 400A inFIG. 9A, each of first anode portion 431, second anode portion 432,third anode portion 433, and fourth anode portion 434 are discrete. Suchdiscrete anode portions may, in some cases, be fabricated via skipcoating or using deposition techniques (e.g., evaporative deposition,vacuum deposition such as sputtering) coupled with the use of one ormore masks.

In some embodiments, the electrochemical device (e.g., foldedelectrochemical device) comprises a continuous anode. For example,referring to FIG. 10A, electrochemical device 400B comprises continuousanode 430. The anode portions of the electrochemical device may be partof the continuous anode. For example, in certain embodiments, the firstanode portion, the second anode portion, the third anode portion, andthe fourth anode portion are part of a continuous anode. Referring toFIG. 10B, first anode portion 431, second anode portion 432, third anodeportion 433, and fourth anode portion 434 are each a part of continuousanode 430. As mentioned, above first anode portion 431 and second anodeportion 432 are part of a continuous anode, at least because thereexists a pathway (e.g., via folded anode region 435) between first anodeportion 431 and second anode portion 432 that is part of the structure(e.g., anode) that includes first anode portion 431 and second anodeportion 432. As mentioned above, in some, but not necessarily all cases,a continuous electrode (e.g., a continuous anode) can provide for foldedelectrochemical devices (e.g., a multi-cell battery) for whichfabrication and the establishment of electrical connections isrelatively facile and inexpensive.

The distinction between anode portions of the electrochemical device(e.g., the first anode portion, the second anode portion, etc.) may beestablished, in some cases, by folds in the electrochemical device. Forexample, in some cases, at least a portion of a continuous anode isfolded to establish a section of the anode on one side of the fold(e.g., a first anode portion) and a section of the anode on the otherside of the fold (e.g., a second anode portion). In other cases, thedistinction between anode portions of the electrochemical device isestablished by the anode portions being discrete anode portions. In somesuch cases, the discrete anode portions are located in sections of theelectrochemical device separated by a fold.

In some embodiments, the active surface portions of certain anodeportions of the folded electrochemical cell face each other. Forexample, in some cases, the second anode surface portion faces the firstanode active surface portion. FIG. 9B depicts a cross-sectional view ofexemplary electrochemical device 400A, where second anode active surfaceportion 442 is facing first anode active surface portion 441, accordingto certain embodiments. In some cases, the fourth anode active surfaceportion faces both the first anode active surface portion and the thirdanode active surface portion. In some such cases, the third anodeportion is at least partially positioned between the first anode portionand the fourth anode portion. FIG. 9B shows an embodiment ofelectrochemical device 400A where third anode portion 433 is at leastpartially positioned between first anode portion 431 and fourth anodeportion 434, and where fourth anode active surface portion 444 is facingboth first anode active surface portion 441 and third anode activesurface portion 443.

As used herein, a surface (or surface portion) is said to be “facing” anobject when the surface and the object are substantially parallel, and aline extending normal to and away from the bulk of the materialcomprising the surface intersects the object. For example, a firstsurface (or first surface portion) and a second surface (or secondsurface portion) can be facing each other if a line normal to the firstsurface and extending away from the bulk of the material comprising thefirst surface intersects the second surface. A surface and a layer canbe facing each other if a line normal to the surface and extending awayfrom the bulk of the material comprising the surface intersects thelayer. A surface can be facing another object when it is in contact withthe other object, or when one or more intermediate materials arepositioned between the surface and the other object. For example, twosurfaces that are facing each other can be in contact or can include oneor more intermediate materials between them.

In some cases, the active surface portions of certain anode portions ofthe folded electrochemical device face away from each other. Forexample, in some cases, the third anode active surface portion facesaway from both the first anode active surface portion and the secondanode active surface portion. FIG. 9B depicts third anode active surfaceportion 443, which is facing away from both first anode active surfaceportion 441 and second anode active surface portion 442.

As used herein, a surface (or surface portion) is said to be “facingaway from” an object when the surface and the object are substantiallyparallel, and no line extending normal to and away from the bulk of thematerial comprising the surface intersects the object. For example, afirst surface (or first surface portion) and a second surface (or secondsurface portion) can be facing away from each other if no line normal tothe first surface and extending away from the bulk of the materialcomprising the first surface intersects the second surface. A surfaceand a layer can be facing away from each other if no line normal to thesurface and extending away from the bulk of the material comprising thesurface intersects the layer. In some embodiments, a surface and anotherobject (e.g., another surface, a layer, etc.) can be substantiallyparallel if the maximum angle defined by the surface and the object isless than about 10°, less than about 5°, less than about 2°, or lessthan about 1°.

In some embodiments, the electrochemical device comprises a plurality ofcathode portions. Each cathode portion of the electrochemical device maycomprise a cathode active surface portion. In some cases, theelectrochemical device comprises a first cathode portion comprising afirst cathode active surface portion, a second cathode portioncomprising a second cathode active surface portion, a third cathodeportion comprising a third cathode active surface portion, and a fourthcathode portion comprising a fourth cathode active surface portion.

In some embodiments, at least some of the cathode portions of theelectrochemical device are discrete (e.g., discrete electrodes). Forexample, in some instances, each of the first cathode portion, thesecond cathode portion, the third cathode portion, and the fourthcathode portion are discrete. Referring to FIG. 9A, electrochemicaldevice 400A comprises first cathode portion 531 comprising first cathodeactive surface portion 541, second cathode portion 532 comprising secondcathode active surface portion 542, third cathode portion 533 comprisingthird cathode active surface portion 543, and fourth cathode portion 534comprising fourth cathode active surface portion 544. In accordance withcertain embodiments of electrochemical device 400A in FIG. 9A, each offirst cathode portion 531, second cathode portion 532, third cathodeportion 533, and fourth cathode portion 534 are discrete. Such discretecathode portions maybe fabricated using any suitable method, such as viaskip coating or using deposition techniques (e.g., evaporativedeposition, vacuum deposition such as sputtering) coupled with the useof one or more masks.

In some embodiments, the electrochemical device (e.g., foldedelectrochemical device) comprises a continuous cathode. The cathodeportions of the electrochemical device may be part of the continuouscathode. For example, in certain embodiments, the first cathode portion,the second cathode portion, the third cathode portion, and the fourthcathode portion are part of a continuous cathode. Though not picturedexplicitly in the FIGS. 9A-10B, first cathode portion 531, secondcathode portion 532, third cathode portion 533, and fourth cathodeportion 544 may, in accordance with certain embodiments, be part of acontinuous cathode.

As with the anode portions described above, the distinction betweencathode portions of the electrochemical device may be established, insome cases, by folds in the electrochemical device. For example, in somecases, at least a portion of a continuous cathode is folded to establisha section of the cathode on one side of the fold (e.g., a first cathodeportion) and a section of the cathode on the other side of the fold(e.g., a second cathode portion). In other cases, the distinctionbetween cathode portions of the electrochemical device is established bythe cathode portions being discrete cathode portions. In some suchcases, the discrete cathode portions are located in sections of theelectrochemical device separated by a fold.

In some embodiments, two electrode portions may be arranged to form adouble-sided electrode, with a first face and second face facing awayfrom the first face, both faces comprising electrode active material andactive surfaces. For example, in some cases, a folded electrochemicaldevice described herein may comprise a double-sided cathode. Onenon-limiting example is an electrochemical device comprising a firstcathode portion and a second cathode portion, with the first cathodeportion forming at least a part of a first side of a double-sidedcathode, and the second cathode portion forming at least a part of asecond side of the double-sided cathode. Such an arrangement is possiblein cases in which the first cathode portion and the second cathodeportion are discrete cathodes, or in cases in which the first cathodeportion and the second cathode portion are part of a continuous cathode.Referring to FIG. 9B, for example, first cathode portion 531 and secondcathode portion 532 form double sided cathode 530, comprising firstcathode active surface portion 541 facing away from second cathodeactive surface portion 542, in accordance with certain embodiments.

In some embodiments, the active surface portions of certain cathodeportions of the folded electrochemical cell face certain anode activesurface portions. For example, in some instances, the first cathodeactive surface portion faces the first anode active surface portion.FIGS. 9B and 10B depict cross-sectional views of exemplaryelectrochemical device 400A and exemplary electrochemical device 400B,respectively, where first cathode active surface portion 541 is facingfirst anode active surface portion 441, according to certainembodiments. In some cases, the second cathode active surface portionfaces the second anode active surface portion, the third cathode activesurface portion faces the third anode active surface portion, and thefourth cathode active surface portion faces the fourth anode activesurface portion. In some, but not necessarily all cases, having therespective cathode active surface portions and anode active surfaceportions facing each other as described herein in results in a foldedelectrochemical device capable of comprising a plurality electrochemicalcells (e.g., upon addition of electrolyte) in a relatively easy tomanufacture and volumetrically energy-dense configuration.

As mentioned above and described in more detail below, in someembodiments, the electrochemical device comprises a separator. Forexample, FIGS. 9A-9B and FIGS. 10A-10B depict exemplary electrochemicaldevice 400A and exemplary electrochemical device 400B, respectively,each of which comprises separator 450. In some cases, such as inembodiments in which the electrochemical devices is folded, theseparator is folded as well. In some cases, the separator is arrangedsuch that a first portion of the separator is between the first anodeportion and the first cathode portion. For example, referring to FIG.9B, first portion 451 of separator 450 is between first anode portion431 and first cathode portion 531. In some cases, the separator isarranged such that it is positioned between multiple anode portions andcathode portions. For example, in some embodiments, the separator isarranged such that a first portion of the separator is between the firstanode portion and the first cathode portion, a second portion of theseparator is between the second anode portion and the second cathodeportion, a third portion of the separator is between the third anodeportion and the third cathode portion, and a fourth portion of theseparator is between the fourth anode portion and the fourth cathodeportion. For example, referring to FIG. 9B, first portion 451 ofseparator 450 is between first anode portion 431 and first cathodeportion 531, second portion 452 of separator 450 is between second anodeportion 432 and second cathode portion 532, third portion 453 ofseparator 450 is between third anode portion 433 and third cathodeportion 533, and fourth portion 454 of separator 450 is between fourthanode portion 434 and fourth cathode portion 534. Such an arrangement isalso depicted in electrochemical device 400B of FIG. 10B comprisingcontinuous anode 430. The separator of the electrochemical device may,in certain cases, be a serpentine separator. For example, separator 450in FIG. 9B is a serpentine separator, in accordance with certainembodiments. A serpentine separator, and other continuous separators,may, in some but not necessarily all embodiments, provide for arelatively easy to manufacture and effective component in foldedelectrochemical devices for providing an electronically insulating butionically conductive pathway for electrochemical reactions whilepreventing problems such as short circuiting.

In some embodiments, the electrochemical device described hereincomprises components arranged in a particular order. For example, theelectrochemical device may comprise a plurality of anode portions, aplurality of cathode portions, and a separator (e.g., a serpentineseparator), with the electrochemical device comprising the following,arranged in the following order: a first anode portion comprising afirst anode active surface portion, a first separator portion, a firstcathode portion comprising a first cathode active surface portion, asecond cathode portion comprising a second cathode active surfaceportion, a second separator portion, a second anode portion comprising asecond anode active surface portion, a third anode portion comprising athird anode active surface portion, a third separator portion, a thirdcathode portion comprising a third cathode active surface portion, afourth cathode portion comprising a fourth cathode active surfaceportion, a fourth separator portion, and a fourth anode portioncomprising a fourth anode active surface portion. FIG. 9B and FIG. 10Bshow exemplary electrochemical device 400A and exemplary electrochemicaldevice 400B, respectively, each of which comprises such componentsarranged in such an order. Specifically, in FIG. 9B, from the left sideof the figure to the right side of the figure, electrochemical device400A comprises the following arranged in order: first anode portion 431comprising first anode active surface portion 441, first separatorportion 451, first cathode portion 531 comprising first cathode activesurface portion 541, second cathode portion 532 comprising secondcathode active surface portion 542, second separator portion 452, secondanode portion 432 comprising second anode active surface portion 442,third anode portion 433 comprising third anode active surface portion443, third separator portion 453, third cathode portion 533 comprisingthird cathode active surface portion 543, fourth cathode portion 534comprising fourth cathode active surface portion 544, fourth separatorportion 454, and fourth anode portion 434 comprising fourth anode activesurface portion 444.

As described above and in more detail below, in some, but notnecessarily all cases, the electrochemical device comprises a substrate.For example, in some cases, one or more electrodes is formed on thesubstrate (optionally with one or more intervening layers, such as acurrent collector). In some cases, one or more of the plurality ofanodes is formed on the substrate. Referring again to FIG. 9A, exemplaryelectrochemical device 400A comprises substrate 420, in accordance withcertain embodiments. In some, but not necessarily all embodiments, thesubstrate is adjacent to one or more of the plurality of anode portions.For example, in some cases, the electrochemical device comprises asubstrate adjacent to each of the first anode portion, the second anodeportion, the third anode portion, and the fourth anode portion.Referring again to FIG. 9B, substrate 420 is adjacent to each of firstanode portion 431, second anode portion 432, third anode portion 433,and fourth anode portion 434. In certain embodiments, the substrate ofthe electrochemical device is continuous. For example, substrate 420 inFIG. 9A may be a continuous sheet comprising a polymer (e.g., a releaselayer), upon which one or more components of the electrochemical deviceis formed, such as a current collector (e.g., a current collectordomain) and/or first anode portion 431, second anode portion 432, thirdanode portion 433, and fourth anode portion 434. In some embodiments,the substrate (e.g., substrate 420) is or comprises a release layer,described in more detail below. In certain cases, when theelectrochemical device is folded, the substrate, or a portion thereof,is located between certain components of the electrochemical device. Insome cases, a portion of the substrate is between the second anodeportion and the third anode portion. For example, in foldedelectrochemical device 400A in FIG. 9B or folded electrochemical device400B in FIG. 10B, substrate portion 421 is between second anode portion432 and third anode portion 433.

The electrochemical devices (e.g., folded electrochemical devices)described herein may comprise one or more current collectors, asmentioned above. In some cases, the electrochemical device comprises ananodic current collector. The anodic current collector may beelectronically coupled to an anode and/or a plurality of anode portionsof the electrochemical device. In some cases, each of the anode portionsof the electrochemical device is electronically coupled to a distinctcurrent collector (e.g., a distinct discrete current collector).However, in some cases, the electrochemical device comprises an anodiccurrent collector electronically coupled to each of the first anodeportion, the second anode portion, the third anode portion, and thefourth anode portion. Each of FIGS. 9A-9B and FIG. 10B depict anelectrochemical device comprising anodic current collector 425. Incertain cases, anodic current collector 425 is electronically coupled toeach of first anode portion 431, second anode portion 432, third anodeportion 433, and fourth anode portion 434. In certain cases, such ananodic current collector is a continuous anodic current collector. Forexample, anodic current collector 425 in FIGS. 9A-9B and FIGS. 10A-10Bis continuous, in accordance with certain embodiments. While certainspecific current collector configurations (e.g., comprising a currentcollector domain comprising a plurality of current collector segmentsand current collector bridges) are described in this disclosure, itshould be understood that in certain cases, the anodic current collectormay comprise other configurations. For example, in some cases, theanodic current collector is a layer of electronically conductivematerial, portions of which are adjacent (e.g., directly adjacent orwith one or more intervening layers) to the first anode portion, thesecond anode portion, the third anode portion, and the fourth anodeportion.

In some embodiments, the electrochemical device comprises a plurality ofcathodic current collectors and/or cathodic current collector portions.As one non-limiting example, electrochemical device may comprise a firstcathodic current collector electronically coupled to the first cathodeportion and a second cathodic current collector electronically coupledto the third cathode portion. Referring to FIG. 9B, electrochemicaldevice 400A comprises optional first cathodic current collector portion524 and optional second cathodic current collector portion 526, inaccordance with certain embodiments. In some cases, the first cathodiccurrent collector portion and the second cathodic current collectorportion are part of a continuous cathodic current collector. The use ofsuch a continuous cathodic current collector, as in the case of theother continuous components described above and below, can provide forfacile manufacturing and a convenient arrangement for forming electricalconnections to the cathodic portions of the folded electrochemicaldevice, in accordance with some but not necessarily all embodiments.While first cathodic current collector portion 524 and second cathodiccurrent collector portion 526 are not shown as being part of acontinuous cathodic current collector in FIG. 9B and FIG. 10B, it shouldbe understood that in some, but not necessarily all embodiments, firstcurrent collector portion 524 and second cathodic current collectorportion 526 are part of a continuous cathodic current collector. Forexample, FIG. 9A and FIG. 10A, which depict partially unfoldedelectrochemical device 400A and electrochemical device 400B,respectively, show continuous cathodic current collector 525, inaccordance with certain embodiments. In some cases, however, the firstcathodic current collector portion and the second cathodic currentcollector portion are discrete. For example, in some, but notnecessarily all embodiments, first cathodic current collector portion524 and second cathodic current collector portion 526 are discretecurrent collectors. In some cases, the electrochemical device comprisesa first cathodic current collector electronically coupled to the firstcathode portion and a second cathodic current collector electronicallycoupled to the third cathode portion. For example, in accordance withcertain embodiments, first current collector portion 524 iselectronically coupled to first cathode portion 531, and second cathodiccurrent collector 526 is electronically coupled to third cathode portion533.

While certain of the electrochemical devices described and illustratedherein are described using a certain number of components (e.g., fouranode portions and four cathode portions), it should be understood thatthe number of components described herein is non-limiting. For example,the electrochemical device may comprise a fifth (or sixth, or more)anode portion comprising a fifth (or sixth, or more) anode activesurface portion and a fifth (or sixth, or more) cathode portioncomprising a fifth (or sixth, or more) cathode active surface portionfacing the fifth (or sixth, or more) anode active surface portion.Additionally, while the electrochemical devices are shown as a “W” fold(e.g., having three folds), in some cases the electrochemical device maycomprise additional folds (and additional anode and cathode portions).For example, in some embodiments, the electrochemical device has atleast 3 folds, at least 4 folds, at least 5 folds, at least 10 folds,and/or up to 12 folds, up to 15 folds, up to 20 folds, or more.

In certain embodiments, the electrochemical device (e.g., a foldedelectrochemical device) is constructed and arranged to avoid problemsassociated with the use of certain anode active materials or certaingeometries. As a non-limiting example, one or more anodes of theelectrochemical device may comprise lithium and/or a lithium alloy as ananode active material, which may form dendrites under certainconditions. As another non-limiting example, one or more anodes of theelectrochemical device may undergo uneven utilization or overutilizationin certain regions of the anode. In some cases, the dimensions and/ororientations of the anode (e.g., anode portions) are configured in orderto address some such problems (e.g., uneven utilization oroverutilization in certain areas).

One such way to avoid certain problems associated with certain anodematerials is to use an “oversized” anode (or anodes) with respect to thecathode of the electrochemical device. For certain of theelectrochemical devices described herein (e.g., folded electrochemicaldevices), an “oversized” anode is accomplished by configuring theelectrochemical device such that a relatively high percentage of theperimeter of the cathode (e.g., cathode portions) is overlapped by anodeactive surface. Specifically, in some embodiments, the electrochemicaldevice comprises a cumulative cathode active surface perimeter definedby the sum of the perimeters of all cathode active surfaces of theelectrochemical device. In cases in which the plurality of cathodeportions are discrete, the cumulative cathode active surface perimeterof the electrochemical device is defined by the sum of the perimeters ofcathode active surfaces of each of the cathode portions. For example,referring to FIG. 11A, if the only cathodes of an exemplaryelectrochemical device are discrete cathode portion 650 having cathodeactive surface 655, discrete cathode portion 660 having cathode activesurface 665, and discrete cathode portion 670 having cathode activesurface 675, then the cumulative cathode active surface perimeter of theelectrochemical device is the sum of the perimeter of cathode activesurface 655 (i.e., cathode perimeter segment 651 plus cathode perimetersegment 652 plus cathode perimeter segment 653 plus cathode perimetersegment 654), the perimeter of cathode active surface 665 (i.e., cathodeperimeter segment 661 plus cathode perimeter segment 662 plus cathodeperimeter segment 663 plus cathode perimeter segment 664), and theperimeter of cathode active surface 675 (i.e., cathode perimeter segment671 plus cathode perimeter segment 672 plus cathode perimeter segment673 plus cathode perimeter segment 674).

As another example, in cases in which the electrochemical devicecomprises a single continuous cathode, the cumulative cathode activesurface perimeter of the electrochemical device is the perimeter of thecathode active surface of that continuous cathode. For example,referring to FIG. 11B, if the only cathode of an exemplary device iscathode 680 having cathode active surface 685, then the cumulativecathode active surface perimeter is the sum of cathode perimeter segment681, cathode perimeter segment 682, cathode perimeter segment 683, andcathode perimeter segment 684.

In some embodiments, a relatively high percentage of the cumulativecathode active surface perimeter of the electrochemical device isoverlapped by anode active surface. Such a configuration, in some butnot necessarily all cases, may be useful in mitigating certain problems,such as dendrite formation in folded electrochemical devices. A point onthe perimeter of a cathode active surface is overlapped by anode activesurface if, on a line that intersects that point and is normal to thecathode perimeter, there exists a point inside the cathode perimeter anda point outside the cathode perimeter that is covered by the anodeactive surface. In other words, a point on the perimeter of the cathodeactive surface is overlapped by anode active surface if the anode activesurface “extends” past the cathode active surface perimeter, rather thaneither not reaching the cathode active surface perimeter point orstopping directly at the cathode active surface perimeter point.

FIG. 12 depicts a top-down view of cathode active surface 640 (indicatedby gray shading). At least a portion of cathode active surface 640 isfacing anode active surface 740 (indicated by diagonal hatching). InFIG. 12 , cathode perimeter segment 632 (which spans from point a topoint b) and cathode perimeter segment 634 (which span from point e topoint f) are each overlapped by anode active surface 740, as indicatedby the solid thick black lines. On the other hand, cathode perimetersegment 622 (which spans from point a to point f) is not overlapped byanode active surface 740 (as indicated by the thick dashed line) becauseanode active surface 740 reaches but does not extend past the cathodeperimeter segment 622. Cathode perimeter segment 623 (which spans frompoint b to point c), cathode perimeter segment 624 (which spans frompoint c to point d), and cathode perimeter segment 625 (which spans frompoint d to point e) are not overlapped by anode active surface 740 (asalso indicated by thick dashed lines) because anode active surface 740does not reach cathode perimeter segment 623, cathode perimeter segment624, or cathode perimeter segment 625. In the case where the cumulativecathode active surface perimeter of cathode active surface 640 isdefined by the sum of cathode perimeter segment 622, cathode perimetersegment 623, cathode perimeter segment 624, cathode perimeter segment625, cathode perimeter segment 632, and cathode perimeter segment 634,the percentage of the cumulative cathode active surface perimeteroverlapped by anode active surface 640 is determined by dividing the sumof cathode perimeter segment 632 and cathode perimeter segment 634 bythe cumulative cathode active surface perimeter. In some embodiments, atleast 60%, at least 75%, at least 90%, at least 95%, at least 99%, orall of the cumulative cathode active surface perimeter is overlapped byanode active surface.

As mentioned above, in some embodiments, the article described above(e.g., comprising a substrate, a current collector bus, a plurality ofdiscrete electrode segments, and optionally current collector segmentsand current collector bridges) is a component of an electrochemicaldevice. FIG. 4 shows a schematic illustration of exemplaryelectrochemical device 200 comprising article 100. In some cases, theelectrochemical cell described herein (e.g., an electrochemical devicecomprising the article having a plurality of discrete electrodesegments) is a multi-cell structure. For example, in FIG. 4 ,electrochemical device 200 is a multi-cell structure. Some suchelectrochemical devices may be useful as part of a battery (e.g., arechargeable lithium ion battery).

The electrochemical device (e.g., comprising the article) may comprise asecond electrode. For example, referring again to FIG. 4 ,electrochemical device 200 comprises second electrode 230. The secondelectrode may comprise or be made of any suitable electrode activematerial. In some embodiments, the second electrode has a polarity thatis the opposite of the polarity of the plurality of the discreteelectrode segments. Generally, two electrodes are of opposite polaritiesif one is an anode and the other is a cathode. For example, in somecases the plurality of discrete electrode segments (e.g., plurality ofdiscrete electrodes segments 130) is a plurality of anodes, and thesecond electrode (e.g., second electrode 230) of the electrochemicaldevice is a cathode. The opposite arrangement is also possible. Incertain cases, the active surface of the plurality of discrete electrodesegments face the active surface of the second electrode. For example,in FIG. 4 , discrete electrode segment 130 a comprises active surface131, second electrode 230 comprises active surface 231, and activesurface 131 faces active surface 231.

Electrical contact can be made with the second electrode using anysuitable technique. For example, the second electrode can be inelectrical contact with a second current collector. FIG. 4 shows secondcurrent collector 225, which is adjacent and electronically coupled tosecond electrode 230. As with the current collector domain describedabove, the second current collector can comprise or be made of anysuitable electronically conductive material (e.g., an electronicallyconductive metal such as aluminum). The second current collector may beimmediately adjacent the second electrode (e.g., second currentcollector 225 may be in direct contact with second electrode 230), orone or more intervening layers (e.g., a primer layer) may be disposedbetween the second electrode and the second current collector (e.g., tofacilitate adhesion between the second electrode and the second currentcollector).

As mentioned above, in some embodiments, the electrochemical devicecomprises a separator interposed between the plurality of discreteelectrode segments and the second electrode. Referring, for example, toFIG. 4 , electrochemical device 200 comprises separator 250 interposedbetween the plurality of discrete electrode segments 130 (e.g., aplurality of anodes) and second electrode 230 (e.g., a cathode). Theseparator may be a solid electronically non-conductive or electronicallyinsulating material which electronically separates the anode and thecathode from each other preventing electronic short circuiting, andwhich permits the transport of ions between the anode and the cathode.In some embodiments, the separator may be porous and may be permeable toan electrolyte. In certain cases the separator is continuous, which maybe useful in cases in which one or more of the electrodes of theelectrochemical device (e.g., the second electrode) is continuous. Forexample, FIG. 4 shows an illustration of separator 250 where separator250 is depicted as being continuous, according to certain embodiments.

The pores of the separator may be partially or substantially filled withelectrolyte. Separators may be supplied as porous free standing filmswhich are interleaved with the anodes and the cathodes during thefabrication of cells. Alternatively, the porous separator layer may beapplied directly to the surface of one of the electrodes, for example,as described in PCT Publication No. WO 99/33125 to Carlson et al. and inU.S. Pat. No. 5,194,341 to Bagley et al.

A variety of separator materials are known in the art. Examples ofsuitable solid porous separator materials include, but are not limitedto, polyolefins, such as, for example, polyethylenes (e.g., SETELA™ madeby Tonen Chemical Corp) and polypropylenes, glass fiber filter papers,and ceramic materials. For example, in some embodiments, the separatorcomprises a microporous polyethylene film. Further examples ofseparators and separator materials suitable for use in theelectrochemical devices (including electrochemical cells) describedherein are those comprising a microporous xerogel layer, for example, amicroporous pseudo-boehmite layer, which may be provided either as afree standing film or by a direct coating application on one of theelectrodes (e.g., the plurality of discrete electrode segments, thesecond electrode), as described in U.S. Pat. Nos. 6,153,337 and6,306,545 by Carlson et al. of the common assignee. Solid electrolytesand gel electrolytes may also function as a separator in addition totheir electrolyte function.

In some embodiments, the electrochemical device comprises a plurality ofdiscrete second electrodes. For example, FIG. 6A shows a non-limitingembodiment of electrochemical device 200 comprising a plurality ofdiscrete second electrodes including second electrode 230(electronically coupled to second current collectors 225), separatedfrom article 100 by separator 250. In accordance with certainembodiments, article 100 in FIG. 6A comprises substrate 120, theplurality of discrete electrode segments 130, plurality of currentcollector segments including current collector segment 122, as well ascurrent collector bridge and a current collector bus not pictured). Incertain cases, the discrete second electrodes are double-sidedelectrodes (e.g., electrodes with a first face and second face facingaway from the first face, both faces comprising electrode activematerial and active surfaces). In some embodiments, electrochemicaldevice 200 can be folded in a similar manner to as described above withrespect to the folding of the article or other exemplary electrochemicaldevices described herein. For example, referring to FIG. 6A, article 100and separator 250 (e.g., a continuous separator) are folded as indicatedand pressed together in the directions indicated by the two blockarrows, with each of the plurality of discrete second electrodes (e.g.,second electrode 230) being covered by folded portions of separator 250,according to certain embodiments. A battery comprising a foldedelectrochemical device (e.g., a folded multi-cell structure as shown inFIG. 6A) may be easier and faster to produce than a battery that has astacked configuration. Electrical connections (e.g., to an externalload) can be made to such embodiments of the electrochemical devicecomprising discrete second electrodes via the discrete second currentcollectors (e.g., second current collectors 225 in FIG. 6A) as well asthe current collector bus of the article (e.g., article 100).

While the plurality of discrete second electrodes are described as beingassociated with discrete second current collectors above, theelectrochemical device may comprise a continuous second currentcollector segment, adjacent to the plurality of discrete secondelectrodes. Such an embodiment may allow for even easier fabrication(e.g., by skip-coating the electrode active material of the secondelectrode on to a continuous electronically conductive layer).

In some embodiments, the electrochemical device comprises a continuoussecond electrode. For example, FIG. 6B shows a non-limiting embodimentof electrochemical device 200 comprising continuous second electrode 230(electronically coupled to second current collector 225), separated fromarticle 100 by continuous separator 250. As in the case with thediscrete second electrodes described above, the embodiment ofelectrochemical device 200 illustrated in FIG. 6B can, in certainembodiments, be folded. For example, referring to FIG. 6B, article 100,separator 250 (e.g., a continuous separator), second electrode 230, andcontinuous second current collector 225 are folded as indicated andpressed together in the directions indicated by the two block arrows,with each of the folded-over portions of second electrode 230 formingeffectively a double-sided electrode that is covered by folded portionsof separator 250, according to certain embodiments. Electricalconnections (e.g., to an external circuit) can be made, for example, atthe folds of the continuous second current collector.

A useful feature of some such folded electrochemical devices comprisinga plurality of discrete second electrodes and/or a continuous secondelectrode electronically coupled to a continuous second currentcollector is that, in some such cases, there is a continuous electronicconduction path available to the second electrode. Therefore, if anelectrical connection between the second current collector to anexternal circuit is disrupted (e.g., due to a manufacturing failure, ordue to damage to the electrochemical device), electrical currentgenerated at the second electrode in an area proximate to the disruptedelectrical connection can flow along the second current collector untilit reaches an undisrupted electrical connection.

In some cases, at least one of the discrete electrode segments in theelectrochemical device loses electronic coupling with the currentcollector bus (e.g., due at least in part to a change in volume of thesubstrate of the article in the electrochemical device). In certaincases, on account of the article having a configuration describedherein, the electrochemical device can still be charged and/ordischarged after the loss of the electronic coupling between the atleast one of the electrode segments and the current collector bus.Referring to FIG. 6B, in some cases, discrete electrode segment 130 aloses electronic coupling with the current collector bus (not pictured)(e.g., due to a heat-induced change in volume of substrate 120).However, electrochemical device 200 in FIG. 6B, in accordance withcertain embodiments, can still be charged/discharged even after the lossof coupling of discrete electrode segment 130 a and the currentcollector bus. That is because the loss of coupling between discreteelectrode segment 130 a and the current collector bus leaves discreteelectrode segment 130 a electronically isolated from the rest ofelectrochemical device 200 (preventing problems such as thermalrunaway), while at least some of the remaining discrete electrodesegments are still electronically coupled to the current collector bus,thereby allowing electrochemical device 200 to be charged/discharged.

As mentioned above, in some embodiments, the substrate of the article oran electrochemical device described herein is or comprises a releaselayer. Release layers described herein are constructed and arranged tohave one or more of the following features: relatively good adhesion toa first layer (e.g., a current collector domain, a plurality of discreteelectrode segments, or in other embodiments, another layer of thesubstrate or other layer) but relatively moderate or poor adhesion to asecond layer (e.g., from a structure used for fabrication of thearticle); high mechanical stability to facilitate delamination withoutmechanical disintegration; high thermal stability; and compatibilitywith processing conditions (e.g., deposition of layers on top of therelease layer, as well as compatibility with techniques used to form therelease layer). Release layers may be thin (e.g., less than about 10microns) to reduce overall battery weight if the release layer isincorporated into the electrochemical device (e.g., electrochemicalcell). A release layer should also be smooth and uniform in thickness soas to facilitate the formation of uniform layers on top of the releaselayer. Furthermore, release layers should be stable in the electrolyteand should not interfere with the structural integrity of the electrodesin order for the electrochemical cell to have a high electrochemical“capacity” or energy storage capability (i.e., reduced capacity fade).The use of release layers to remove a objects from one or morecomponents of an electrochemical device are described in detail in U.S.patent application Ser. No. 12/862,513, filed on Aug. 24, 2010, entitled“Release System for Electrochemical Cells.”

The substrate and/or release layer may be formed of, for example, aceramic, a polymer, or a combination thereof. As such, the substrateand/or release layer may be semi-conductive or insulating. In someembodiments, the substrate and/or release layer comprises a polymericmaterial. In some cases, at least a portion of the polymeric material ofthe substrate and/or release layer is crosslinked; in other cases, thepolymeric material(s) is substantially uncrosslinked. Examples ofpolymeric materials include, for example, hydroxyl-containing polymerssuch as poly vinyl alcohol, polyvinyl butyral, polyvinyl formal, vinylacetate-vinyl alcohol copolymers, ethylene-vinyl alcohol copolymers, andvinyl alcohol-methyl methacrylate copolymers. As mentioned above, insome but not necessarily all embodiments, the substrate (e.g., includinga release layer) comprise a heat-shrinkable film.

The electrodes described herein (e.g., the plurality of discreteelectrode segments, the second electrode of the electrochemical device)can be anodes comprising a variety of anode active materials. Forexample, the anode may comprise a lithium-containing material, whereinlithium is the anode active material. Suitable electroactive materialsfor use as anode active materials in the anodes described hereininclude, but are not limited to, lithium metal such as lithium foil andlithium deposited onto a conductive substrate, and lithium alloys (e.g.,lithium-aluminum alloys and lithium-tin alloys). Methods for depositinga negative electrode material (e.g., an alkali metal anode such aslithium) onto a substrate may include methods such as thermalevaporation, sputtering, jet vapor deposition, and laser ablation.Alternatively, where the anode comprises a lithium foil, or a lithiumfoil and a substrate, these can be laminated together by a laminationprocess as known in the art to form an anode.

In some embodiments, the anode is an electrode from which lithium ionsare liberated during discharge and into which the lithium ions areintegrated (e.g., intercalated) during charge. In some embodiments, theanode active material is a lithium intercalation compound (e.g., acompound that is capable of reversibly inserting lithium ions at latticesites and/or interstitial sites). In some embodiments, the anode activematerial comprises carbon. In certain cases, the anode active materialis or comprises a graphitic material (e.g., graphite). A graphiticmaterial generally refers to a material that comprises a plurality oflayers of graphene (i.e., layers comprising carbon atoms covalentlybonded in a hexagonal lattice). Adjacent graphene layers are typicallyattracted to each other via van der Waals forces, although covalentbonds may be present between one or more sheets in some cases. In somecases, the carbon-comprising anode active material is or comprises coke(e.g., petroleum coke). In certain embodiments, the anode activematerial comprises silicon, lithium, and/or any alloys of combinationsthereof. In certain embodiments, the anode active material compriseslithium titanate (Li₄Ti₅Oi₂, also referred to as “LTO”), tin-cobaltoxide, or any combinations thereof.

In one embodiment, an electroactive lithium-containing material of ananode comprises greater than 50% by weight of lithium. In anotherembodiment, the electroactive lithium-containing material of an anodecomprises greater than 75% by weight of lithium. In yet anotherembodiment, the electroactive lithium-containing material of an anodecomprises greater than 90% by weight of lithium. Additional materialsand arrangements suitable for use in the anode are described, forexample, in U.S. Patent Publication No. 2010/0035128 to Scordilis-Kelleyet al. filed on Aug. 4, 2009, entitled “Application of Force inElectrochemical Cells,” which is incorporated herein by reference in itsentirety for all purposes.

The electrodes described herein (e.g., the plurality of discreteelectrode segments, the second electrode of the electrochemical device)can be cathodes comprising cathode active material. Suitableelectroactive materials for use as cathode active materials in thecathodes include, but are not limited to, one or more metal oxides, oneor more intercalation materials, electroactive transition metalchalcogenides, electroactive conductive polymers, sulfur, carbon and/orcombinations thereof.

In some embodiments, the cathode active material comprises one or moremetal oxides. In some embodiments, an intercalation cathode (e.g., alithium-intercalation cathode) may be used. Non-limiting examples ofsuitable materials that may intercalate ions of an electroactivematerial (e.g., alkaline metal ions) include metal oxides, titaniumsulfide, and iron sulfide. In some embodiments, the cathode is anintercalation cathode comprising a lithium transition metal oxide or alithium transition metal phosphate. Additional examples includeLi_(x)CoO₂ (e.g., Li_(1.1)CoO₂), Li_(x)NiO₂, Li_(x)MnO₂, Li_(x)Mn₂O₄(e.g., Li_(1.05)Mn₂O₄), Li_(x)CoPO₄, Li_(x)MnPO₄, LiCo_(x)Ni_((1-x))O₂,and LiCo_(x)Ni_(y)Mn_((1-x-y))O₂ (e.g., LiNi_(1/3)Mn_(1/3)Co_(1/3)O₂,LiNi_(3/5)Mn_(1/5)Co_(1/5)O₂, LiNi_(4/5)Mn_(1/10)Co_(1/10)O₂,LiNi_(1/2)Mn_(3/10)Co_(1/5)O₂). X may be greater than or equal to 0 andless than or equal to 2. X is typically greater than or equal to 1 andless than or equal to 2 when the electrochemical device is fullydischarged, and less than 1 when the electrochemical device is fullycharged. In some embodiments, a fully charged electrochemical device mayhave a value of x that is greater than or equal to 1 and less than orequal to 1.05, greater than or equal to 1 and less than or equal to 1.1,or greater than or equal to 1 and less than or equal to 1.2. Furtherexamples include Li_(x)NiPO₄, where (0<x≤1), LiMn_(x)Ni_(y)O₄ where(x+y=2) (e.g., LiMn_(1.5)Ni_(0.5)O₄), LiNi_(x)Co_(y)Al_(z)O₂ where(x+y+z=1), LiFePO₄, and combinations thereof. In some embodiments, theelectroactive material within the cathode comprises lithium transitionmetal phosphates (e.g., LiFePO₄), which can, in certain embodiments, besubstituted with borates and/or silicates.

As noted above, in some embodiments, the cathode active materialcomprises one or more chalcogenides. As used herein, the term“chalcogenides” pertains to compounds that contain one or more of theelements of oxygen, sulfur, and selenium. Examples of suitabletransition metal chalcogenides include, but are not limited to, theelectroactive oxides, sulfides, and selenides of transition metalsselected from the group consisting of Mn, V, Cr, Ti, Fe, Co, Ni, Cu, Y,Zr, Nb, Mo, Ru, Rh, Pd, Ag, Hf, Ta, W, Re, Os, and Ir. In oneembodiment, the transition metal chalcogenide is selected from the groupconsisting of the electroactive oxides of nickel, manganese, cobalt, andvanadium, and the electroactive sulfides of iron. In one embodiment, acathode includes one or more of the following materials: manganesedioxide, iodine, silver chromate, silver oxide and vanadium pentoxide,copper oxide, copper oxyphosphate, lead sulfide, copper sulfide, ironsulfide, lead bismuthate, bismuth trioxide, cobalt dioxide, copperchloride, manganese dioxide, and carbon. In another embodiment, thecathode active layer comprises an electroactive conductive polymer.Examples of suitable electroactive conductive polymers include, but arenot limited to, electroactive and electronically conductive polymersselected from the group consisting of polypyrroles, polyanilines,polyphenylenes, polythiophenes, and polyacetylenes. Examples ofconductive polymers include polypyrroles, polyanilines, andpolyacetylenes.

In some embodiments, electroactive materials for use as cathode activematerials in cathodes described herein include electroactivesulfur-containing materials. “Electroactive sulfur-containingmaterials,” as used herein, relates to cathode active materials whichcomprise the element sulfur in any form, wherein the electrochemicalactivity involves the oxidation or reduction of sulfur atoms ormoieties. The nature of the electroactive sulfur-containing materialsuseful in the practice of this invention may vary widely, as known inthe art. For example, in one embodiment, the electroactivesulfur-containing material comprises elemental sulfur. In anotherembodiment, the electroactive sulfur-containing material comprises amixture of elemental sulfur and a sulfur-containing polymer. Thus,suitable electroactive sulfur-containing materials may include, but arenot limited to, elemental sulfur and organic materials comprising sulfuratoms and carbon atoms, which may or may not be polymeric. Suitableorganic materials include those further comprising heteroatoms,conductive polymer segments, composites, and conductive polymers.

In some embodiments, an electroactive sulfur-containing material of acathode active material comprises greater than 50% by weight of sulfur.In another embodiment, the electroactive sulfur-containing materialcomprises greater than 75% by weight of sulfur. In yet anotherembodiment, the electroactive sulfur-containing material comprisesgreater than 90% by weight of sulfur.

The cathodes of the present invention may comprise from about 20 to 100%by weight of electroactive cathode materials (e.g., as measured after anappropriate amount of solvent has been removed from the cathode activelayer and/or after the layer has been appropriately cured). In oneembodiment, the amount of electroactive sulfur-containing material inthe cathode is in the range of 5-30% by weight of the cathode. Inanother embodiment, the amount of electroactive sulfur-containingmaterial in the cathode is in the range of 20% to 90% by weight of thecathode.

Additional materials suitable for use in the cathode, and suitablemethods for making the cathodes, are described, for example, in U.S.Pat. No. 5,919,587, filed May 21, 1997, entitled “Novel CompositeCathodes, Electrochemical Cells Comprising Novel Composite Cathodes, andProcesses for Fabricating Same,” and U.S. Patent Publication No.2010/0035128 to Scordilis-Kelley et al. filed on Aug. 4, 2009, entitled“Application of Force in Electrochemical Cells,” each of which isincorporated herein by reference in its entirety for all purposes.

In some embodiments, an electrode (e.g., a discrete electrode segment,an anode portion) of the electrochemical device may comprise one or morecoatings or layers formed from polymers, ceramics, and/or glasses. Thecoating may serve as a protective layer and may serve differentfunctions. Those functions may include preventing the formation ofdendrites during recharging which could otherwise cause shortcircuiting, preventing reaction of the electrode active material withelectrolyte, and improving cycle life. Examples of such protectivelayers include those described in: U.S. Pat. No. 8,338,034 to Affinitoet al. and U.S. Patent Publication No. 2015/0236322 to Laramie at al.,each of which is incorporated herein by reference in its entirety forall purposes.

The electrochemical devices described herein may comprise anelectrolyte. The electrolyte can function as a medium for the storageand transport of ions, and in the special case of solid electrolytes andgel electrolytes, these materials may additionally function as aseparator between an anode and a cathode. Any liquid, solid, or gelmaterial capable of storing and transporting ions may be used, so longas the material facilitates the transport of ions (e.g., lithium ions)between an anode and the cathode. The electrolyte is electronicallynon-conductive to prevent short circuiting between an anode and acathode. In some embodiments, the electrolyte may comprise a non-solidelectrolyte.

In some embodiments, the electrolyte comprises a fluid that can be addedat any point in the fabrication process. In some cases, theelectrochemical device may be fabricated by providing a cathode and ananode, applying an anisotropic force component normal to the activesurface of the anode, and subsequently adding the fluid electrolyte suchthat the electrolyte is in electrochemical communication with thecathode and the anode. In other cases, the fluid electrolyte may beadded to the electrochemical device prior to or simultaneously with theapplication of an anisotropic force component, after which theelectrolyte is in electrochemical communication with the cathode and theanode.

The electrolyte can comprise one or more ionic electrolyte salts toprovide ionic conductivity and one or more liquid electrolyte solvents,gel polymer materials, or polymer materials. Suitable non-aqueouselectrolytes may include organic electrolytes comprising one or morematerials selected from the group consisting of liquid electrolytes, gelpolymer electrolytes, and solid polymer electrolytes. Examples ofnon-aqueous electrolytes for lithium batteries are described by Dornineyin Lithium Batteries, New Materials, Developments and Perspectives,Chapter 4, pp. 137-165, Elsevier, Amsterdam (1994). Examples of gelpolymer electrolytes and solid polymer electrolytes are described byAlamgir et al. in Lithium Batteries, New Materials, Developments andPerspectives, Chapter 3, pp. 93-136, Elsevier, Amsterdam (1994).Heterogeneous electrolyte compositions that can be used in batteriesdescribed herein are described in U.S. patent application Ser. No.12/312,764, filed May 26, 2009 and entitled “Separation ofElectrolytes,” by Mikhaylik et al., which is incorporated herein byreference in its entirety.

Examples of useful non-aqueous liquid electrolyte solvents include, butare not limited to, non-aqueous organic solvents, such as, for example,N-methyl acetamide, acetonitrile, acetals, ketals, esters, carbonates,sulfones, sulfites, sulfolanes, aliphatic ethers, cyclic ethers, glymes,polyethers, phosphate esters, siloxanes, dioxolanes,N-alkylpyrrolidones, substituted forms of the foregoing, and blendsthereof. Fluorinated derivatives of the foregoing are also useful asliquid electrolyte solvents.

In some cases, aqueous solvents can be used as electrolytes, forexample, in lithium cells. Aqueous solvents can include water, which cancontain other components such as ionic salts. As noted above, in someembodiments, the electrolyte can include species such as lithiumhydroxide, or other species rendering the electrolyte basic, so as toreduce the concentration of hydrogen ions in the electrolyte.

Liquid electrolyte solvents can also be useful as plasticizers for gelpolymer electrolytes, i.e., electrolytes comprising one or more polymersforming a semi-solid network. Examples of useful gel polymerelectrolytes include, but are not limited to, those comprising one ormore polymers selected from the group consisting of polyethylene oxides,polypropylene oxides, polyacrylonitriles, polysiloxanes, polyimides,polyphosphazenes, polyethers, sulfonated polyimides, perfluorinatedmembranes (NAFION resins), polydivinyl polyethylene glycols,polyethylene glycol diacrylates, polyethylene glycol dimethacrylates,polysulfones, polyethersulfones, derivatives of the foregoing,copolymers of the foregoing, crosslinked and network structures of theforegoing, and blends of the foregoing, and optionally, one or moreplasticizers. In some embodiments, a gel polymer electrolyte comprisesbetween 10-20%, between 20-40%, between 60-70%, between 70-80%, between80-90%, or between 90-95% of a heterogeneous electrolyte by volume.

In some embodiments, one or more solid polymers can be used to form anelectrolyte. Examples of useful solid polymer electrolytes include, butare not limited to, those comprising one or more polymers selected fromthe group consisting of polyethers, polyethylene oxides, polypropyleneoxides, polyimides, polyphosphazenes, polyacrylonitriles, polysiloxanes,derivatives of the foregoing, copolymers of the foregoing, crosslinkedand network structures of the foregoing, and blends of the foregoing.

In addition to electrolyte solvents, gelling agents, and polymers asknown in the art for forming electrolytes, the electrolyte may furthercomprise one or more ionic electrolyte salts, also as known in the art,to increase the ionic conductivity.

Examples of ionic electrolyte salts for use in the electrolyte of theelectrochemical devices (e.g., electrochemical cells) described hereininclude, but are not limited to, LiSCN, LiBr, LiI, LiClO₄, LiAsF₆,LiSO₃CF₃, LiSO₃CH₃, LiBF₄, LiB(Ph)₄, LiPF₆, LiC(SO₂CF₃)₃, LiN(SO₂CF₃)₂,and lithium bis(fluorosulfonyl)imide (LiFSI). Other electrolyte saltsthat may be useful include lithium polysulfides (Li₂S_(x)), and lithiumsalts of organic polysulfides (LiS_(x)R)_(n), where x is an integer from1 to 20, n is an integer from 1 to 3, and R is an organic group, andthose disclosed in U.S. Pat. No. 5,538,812 to Lee et al., which isincorporated herein by reference in its entirety for all purposes.

In some embodiments, the electrolyte comprises one or more roomtemperature ionic liquids. The room temperature ionic liquid, ifpresent, typically comprises one or more cations and one or more anions.Non-limiting examples of suitable cations include lithium cations and/orone or more quaternary ammonium cations such as imidazolium,pyrrolidinium, pyridinium, tetraalkylammonium, pyrazolium, piperidinium,pyridazinium, pyrimidinium, pyrazinium, oxazolium, and trizoliumcations. Non-limiting examples of suitable anions includetrifluromethylsulfonate (CF₃SO₃ ⁻), bis (fluorosulfonyl)imide (N(FSO₂)₂⁻, bis (trifluoromethyl sulfonyl)imide ((CF₃SO₂)₂N⁻, bis(perfluoroethylsulfonyl)imide ((CF₃CF₂SO₂)₂N⁻ andtris(trifluoromethylsulfonyl)methide ((CF₃SO₂)₃C⁻. Non-limiting examplesof suitable ionic liquids includeN-methyl-N-propylpyrrolidinium/bis(fluorosulfonyl) imide and1,2-dimethyl propylimidazolium/bis(trifluoromethanesulfonyl)imide. Insome embodiments, the electrolyte comprises both a room temperatureionic liquid and a lithium salt. In some other embodiments, theelectrolyte comprises a room temperature ionic liquid and does notinclude a lithium salt.

In some embodiments described herein, a force, or forces, is applied toportions of an electrochemical device. Such application of force mayreduce irregularity or roughening of an electrode surface of the cell(e.g., when lithium metal or lithium alloy anodes are employed), therebyimproving performance. Electrochemical devices in which anisotropicforces are applied and methods for applying such forces are described,for example, in U.S. Pat. No. 9,105,938, issued Aug. 11, 2015, publishedas U.S. Patent Publication No. 2010/0035128 on Feb. 11, 2010, andentitled “Application of Force in Electrochemical Cells,” which isincorporated herein by reference in its entirety for all purposes.

The force may comprise, in some instances, an anisotropic force with acomponent normal to an active surface of the anode of theelectrochemical device. In the embodiments described herein,electrochemical devices (e.g., rechargeable batteries) may undergo acharge/discharge cycle involving deposition of metal (e.g., lithiummetal or other active material) on a surface of the anode upon chargingand reaction of the metal on the anode surface, wherein the metaldiffuses from the anode surface, upon discharging. The uniformity withwhich the metal is deposited on the anode may affect cell performance.For example, when lithium metal is removed from and/or redeposited on ananode, it may, in some cases, result in an uneven surface. For example,upon redeposition it may deposit unevenly forming a rough surface. Theroughened surface may increase the amount of lithium metal available forundesired chemical reactions which may result in decreased cyclinglifetime and/or poor cell performance. The application of force to theelectrochemical device has been found, in accordance with certainembodiments described herein, to reduce such behavior and to improve thecycling lifetime and/or performance of the cell.

In some embodiments, the electrochemical device is constructed andarranged to apply, during at least one period of time during chargeand/or discharge of the device, an anisotropic force with a componentnormal to the first anode active surface portion. Referring back to FIG.9B, which illustrates an exemplary folded electrochemical device asdescribed herein, a force may be applied in the direction of arrow 481.Arrow 482 illustrates the component of force 481 that is normal to firstanode active surface portion 441 of first anode portion 431 as well asfirst cathode active surface portion 541 of first cathode portion 531.

In some embodiments, an anisotropic force with a component normal to anactive surface of the anode is applied during at least one period oftime during charge and/or discharge of the electrochemical device. Insome embodiments, the force may be applied continuously, over one periodof time, or over multiple periods of time that may vary in durationand/or frequency. The anisotropic force may be applied, in some cases,at one or more pre-determined locations, optionally distributed over anactive surface of the anode. In some embodiments, the anisotropic forceis applied uniformly over one or more active surfaces of the anode.

An “anisotropic force” is given its ordinary meaning in the art andmeans a force that is not equal in all directions. A force equal in alldirections is, for example, internal pressure of a fluid or materialwithin the fluid or material, such as internal gas pressure of anobject. Examples of forces not equal in all directions include forcesdirected in a particular direction, such as the force on a table appliedby an object on the table via gravity. Another example of an anisotropicforce includes certain forces applied by a band arranged around aperimeter of an object. For example, a rubber band or turnbuckle canapply forces around a perimeter of an object around which it is wrapped.However, the band may not apply any direct force on any part of theexterior surface of the object not in contact with the band. Inaddition, when the band is expanded along a first axis to a greaterextent than a second axis, the band can apply a larger force in thedirection parallel to the first axis than the force applied parallel tothe second axis.

A force with a “component normal” to a surface, for example an activesurface of an anode, is given its ordinary meaning as would beunderstood by those of ordinary skill in the art and includes, forexample, a force which at least in part exerts itself in a directionsubstantially perpendicular to the surface. Those of ordinary skill canunderstand other examples of these terms, especially as applied withinthe description of this document.

In some embodiments, the anisotropic force can be applied such that themagnitude of the force is substantially equal in all directions within aplane defining a cross-section of the electrochemical device, but themagnitude of the forces in out-of-plane directions is substantiallyunequal to the magnitudes of the in-plane forces.

In one set of embodiments, cells described herein are constructed andarranged to apply, during at least one period of time during chargeand/or discharge of the cell, an anisotropic force with a componentnormal to the active surface of the anode. Those of ordinary skill inthe art will understand the meaning of this. In such an arrangement, thecell may be formed as part of a container which applies such a force byvirtue of a “load” applied during or after assembly of the cell, orapplied during use of the cell as a result of expansion and/orcontraction of one or more portions of the cell itself.

The magnitude of the applied force is, in some embodiments, large enoughto enhance the performance of the electrochemical device. An anodeactive surface and the anisotropic force may be, in some instances,together selected such that the anisotropic force affects surfacemorphology of the anode active surface to inhibit increase in anodeactive surface area through charge and discharge and wherein, in theabsence of the anisotropic force but under otherwise essentiallyidentical conditions, the anode active surface area is increased to agreater extent through charge and discharge cycles. “Essentiallyidentical conditions,” in this context, means conditions that aresimilar or identical other than the application and/or magnitude of theforce. For example, otherwise identical conditions may mean a cell thatis identical, but where it is not constructed (e.g., by brackets orother connections) to apply the anisotropic force on the subject cell.

In some embodiments, an anisotropic force with a component normal to anactive surface of the anode is applied, during at least one period oftime during charge and/or discharge of the electrochemical device, to anextent effective to inhibit an increase in surface area of the anodeactive surface relative to an increase in surface area absent theanisotropic force. The component of the anisotropic force normal to theanode active surface may, for example, define a pressure of at leastabout 4.9, at least about 9.8, at least about 24.5, at least about 49,at least about 78, at least about 98, at least about 117.6, at leastabout 147, at least about 175, at least about 200, at least about 225,or at least about 250 Newtons per square centimeter. In someembodiments, the component of the anisotropic force normal to the anodeactive surface may, for example, define a pressure of less than about250, less than about 225, less than about 196, less than about 147, lessthan about 117.6, less than about 98, less than about 49, less thanabout 24.5, or less than about 9.8 Newtons per square centimeter. Insome cases, the component of the anisotropic force normal to the anodeactive surface may define a pressure of between about 4.9 and about 147Newtons per square centimeter, between about 49 and about 117.6 Newtonsper square centimeter, between about 68.6 and about 98 Newtons persquare centimeter, between about 78 and about 108 Newtons per squarecentimeter, between about 4.9 and about 250 Newtons per squarecentimeter, between about 49 and about 250 Newtons per squarecentimeter, between about 80 and about 250 Newtons per squarecentimeter, between about 90 and about 250 Newtons per squarecentimeter, or between about 100 and about 250 Newtons per squarecentimeter. The force or pressure may, in some embodiments, beexternally-applied to the cell, as described herein. While forces andpressures are generally described herein in units of Newtons and Newtonsper unit area, respectively, forces and pressures can also be expressedin units of kilograms-force (kgf) and kilograms-force per unit area,respectively. One of ordinary skill in the art will be familiar withkilogram-force-based units, and will understand that 1 kilogram-force isequivalent to about 9.8 Newtons.

As described herein, in some embodiments, the surface of an anode can beenhanced during cycling (e.g., for lithium, the development of mossy ora rough surface of lithium may be reduced or eliminated) by applicationof an externally-applied (in some embodiments, uniaxial) pressure. Theexternally-applied pressure may, in some embodiments, be chosen to begreater than the yield stress of a material forming the anode. Forexample, for an anode comprising lithium, the cell may be under anexternally-applied anisotropic force with a component defining apressure of at least about 8 kgf/cm², at least about 9 kgf/cm², at leastabout 10 kgf/cm², at least about 20 kgf/cm², at least about 30 kgf/cm²,at least about 40 kgf/cm², or at least about 50 kgf/cm². This is becausethe yield stress of lithium is around 7-8 kgf/cm². Thus, at pressures(e.g., uniaxial pressures) greater than this value, mossy Li, or anysurface roughness at all, may be reduced or suppressed. The lithiumsurface roughness may mimic the surface that is pressing against it.Accordingly, when cycling under at least about 8 kgf/cm², at least about9 kgf/cm², at least about 10 kgf/cm², at least about 20 kgf/cm², atleast about 30 kgf/cm², at least about 40 kgf/cm², or at least about 50kgf/cm² of externally-applied pressure, the lithium surface may becomesmoother with cycling when the pressing surface is smooth. As describedherein, the pressing surface may be modified by choosing the appropriatematerial(s) positioned between the anode and the cathode.

In some cases, one or more forces applied to the cell have a componentthat is not normal to an active surface of an anode. For example, inFIG. 9B force 484 is not normal to first anode active surface portion441. In one set of embodiments, the sum of the components of all appliedanisotropic forces in a direction normal to the anode active surface islarger than any sum of components in a direction that is non-normal tothe anode active surface. In some embodiments, the sum of the componentsof all applied anisotropic forces in a direction normal to the anodeactive surface is at least about 5%, at least about 10%, at least about20%, at least about 35%, at least about 50%, at least about 75%, atleast about 90%, at least about 95%, at least about 99%, or at leastabout 99.9% larger than any sum of components in a direction that isparallel to the anode active surface.

The anisotropic force described herein may be applied using any suitablemethod known in the art. In some embodiments, the force may be appliedusing compression springs. For example, the electrochemical device maybe situated in an optional enclosed containment structure with one ormore compression springs situated between current collector and/orcurrent collector and the adjacent wall of containment structure toproduce a force with a component in normal to an anode active surface(e.g., an anode active surface portion). In some embodiments, the forcemay be applied by situating one or more compression springs outside thecontainment structure such that the spring is located between an outsidesurface of the containment structure and another surface (e.g., atabletop, the inside surface of another containment structure, anadjacent cell, etc.). Forces may be applied using other elements (eitherinside or outside a containment structure) including, but not limited toBelleville washers, machine screws, pneumatic devices, and/or weights,among others. For example, in one set of embodiments, one or more cells(e.g., a folded multi-cell system as described herein) are arrangedbetween two plates (e.g., metal plates). A device (e.g., a machinescrew, a spring, etc.) may be used to apply pressure to the ends of thecell or stack via the plates. In the case of a machine screw, forexample, the cells may be compressed between the plates upon rotatingthe screw. As another example, in some embodiments, one or more wedgesmay be displaced between a surface of the cell (or the containmentstructure surrounding the cell) and a fixed surface (e.g., a tabletop,the inside surface of another containment structure, an adjacent cell,etc.). The anisotropic force may be applied by driving the wedge betweenthe cell and the adjacent fixed surface through the application of forceon the wedge (e.g., by turning a machine screw).

In some cases, electrochemical devices may be pre-compressed before theyare inserted into containment structures, and, upon being inserted tothe containment structure, they may expand to produce a net force on thecell. Such an arrangement may be advantageous, for example, if the cellis capable of withstanding relatively high variations in pressure. Insuch embodiments, the containment structures may have a relatively highstrength (e.g., at least about 100 MPa, at least about 200 MPa, at leastabout 500 MPa, or at least about 1 GPa). In addition, the containmentstructure may have a relatively high elastic modulus (e.g., at leastabout 10 GPa, at least about 25 GPa, at least about 50 GPa, or at leastabout 100 GPa). The containment structure may comprise, for example,aluminum, titanium, or any other suitable material.

In some embodiments, the use of certain electronically insulatingregions and/or methods described herein may result in improved capacityafter repeated cycling of the electrochemical device. For example, insome embodiments, after alternatively discharging and charging the cellthree times, the cell exhibits at least about 50%, at least about 80%,at least about 90%, or at least about 95% of the cell's initial capacityat the end of the third cycle. In some cases, after alternativelydischarging and charging the cell ten times, the cell exhibits at leastabout 50%, at least about 80%, at least about 90%, or at least about 95%of the cell's initial capacity at the end of the tenth cycle. In stillfurther cases, after alternatively discharging and charging the celltwenty-five times, the cell exhibits at least about 50%, at least about80%, at least about 90%, or at least about 95% of the cell's initialcapacity at the end of the twenty-fifth cycle. In some embodiments, theelectrochemical device has a capacity of at least 20 mAh, 30 mAh, 40mAh, 50 mAh, 60 mAh, 70 mAh, or 80 mAh at the end of the cell's third,10th, 25th, 30th, 40th, 45th, 50th, or 60th cycle.

It should be understood that when a portion (e.g., layer, structure,region) is “on”, “adjacent”, “above”, “over”, “overlying”, or “supportedby” another portion, it can be directly on the portion, or anintervening portion (e.g., layer, structure, region) also may bepresent. Similarly, when a portion is “below” or “underneath” anotherportion, it can be directly below the portion, or an intervening portion(e.g., layer, structure, region) also may be present. A portion that is“directly on”, “directly adjacent”, “immediately adjacent”, “in directcontact with”, or “directly supported by” another portion means that nointervening portion is present. It should also be understood that when aportion is referred to as being “on”, “above”, “adjacent”, “over”,“overlying”, “in contact with”, “below”, or “supported by” anotherportion, it may cover the entire portion or a part of the portion.

As described above, certain embodiments of the inventive systems and/ormethods include one or more processors, for example, associated with asensor. The processor may be part of, according to certain embodiments,a computer-implemented control system. The computer-implemented controlsystem can be used to operate various components of the system. Ingeneral, any calculation methods, steps, simulations, algorithms,systems, and system elements described herein may be implemented and/orcontrolled using one or more computer-implemented control system(s),such as the various embodiments of computer-implemented systemsdescribed below. The methods, steps, control systems, and control systemelements described herein are not limited in their implementation to anyspecific computer system described herein, as many other differentmachines may be used.

The computer-implemented control system can be part of or coupled inoperative association with one or more articles (e.g., electrochemicalcells) and/or other system components that might be automated, and, insome embodiments, is configured and/or programmed to control and adjustoperational parameters, as well as analyze and calculate values, forexample any of the values described above. In some embodiments, thecomputer-implemented control system(s) can send and receive referencesignals to set and/or control operating parameters of system apparatus.In other embodiments, the computer-implemented system(s) can be separatefrom and/or remotely located with respect to the other system componentsand may be configured to receive data from one or more inventive systemsvia indirect and/or portable means, such as via portable electronic datastorage devices, such as magnetic disks, or via communication over acomputer network, such as the Internet or a local intranet.

The computer-implemented control system(s) may include several knowncomponents and circuitry, including a processor, a memory system, inputand output devices and interfaces (e.g., an interconnection mechanism),as well as other components, such as transport circuitry (e.g., one ormore busses), a video and audio data input/output (I/O) subsystem,special-purpose hardware, as well as other components and circuitry, asdescribed below in more detail. Further, the computer system(s) may be amulti-processor computer system or may include multiple computersconnected over a computer network.

The computer-implemented control system(s) may include a processor, forexample, a commercially available processor such as one of the seriesx86; Celeron, Pentium, and Core processors, available from Intel;similar devices from AMD and Cyrix; the 680X0 series microprocessorsavailable from Motorola; and the PowerPC microprocessor from IBM. Manyother processors are available, and the computer system is not limitedto a particular processor.

A processor typically executes a program called an operating system, ofwhich WindowsNT, Windows95 or 98, Windows XP, Windows Vista, Windows 7,Windows 10, UNIX, Linux, DOS, VMS, MacOS, OS8, and OS X are examples,which controls the execution of other computer programs and providesscheduling, debugging, input/output control, accounting, compilation,storage assignment, data management and memory management, communicationcontrol and related services. The processor and operating systemtogether define, in accordance with certain embodiments, a computerplatform for which application programs in high-level programminglanguages are written. The computer-implemented control system is notlimited to a particular computer platform.

In accordance with certain embodiments, the processor generallymanipulates the data within the integrated circuit memory element inaccordance with the program instructions and then copies the manipulateddata to the non-volatile recording medium after processing is completed.A variety of mechanisms are known for managing data movement between thenon-volatile recording medium and the integrated circuit memory element,and the computer-implemented control system(s) that implements themethods, steps, systems control and system elements control describedabove is not limited thereto. The computer-implemented control system(s)is not limited to a particular memory system.

At least part of such a memory system described above may be used tostore one or more data structures (e.g., look-up tables) or equationssuch as calibration curve equations. For example, at least part of thenon-volatile recording medium may store at least part of a database thatincludes one or more of such data structures. Such a database may be anyof a variety of types of databases, for example, a file system includingone or more flat-file data structures where data is organized into dataunits separated by delimiters, a relational database where data isorganized into data units stored in tables, an object-oriented databasewhere data is organized into data units stored as objects, another typeof database, or any combination thereof.

It should be appreciated that one or more of any type ofcomputer-implemented control system may be used to implement variousembodiments described herein. Aspects of the invention may beimplemented in software, hardware or firmware, or any combinationthereof. The computer-implemented control system(s) may includespecially programmed, special purpose hardware, for example, anapplication-specific integrated circuit (ASIC). Such special-purposehardware may be configured to implement one or more of the methods,steps, algorithms, systems control, and/or system elements controldescribed above as part of the computer-implemented control system(s)described above or as an independent component.

The computer-implemented control system(s) and components thereof may beprogrammable using any of a variety of one or more suitable computerprogramming languages. In addition, the methods, steps, algorithms,systems control, and/or system elements control may be implemented usingany of a variety of suitable programming languages. Such languages mayinclude procedural programming languages, for example, LabView, C,Pascal, Fortran, and BASIC, object-oriented languages, for example, C++,Java, and Eiffel, and other languages, such as a scripting language oreven assembly language. In some embodiments, the computer programminglanguage is Python. In some embodiments, the computer programminglanguage is SQL.

Such methods, steps, algorithms, systems control, and/or system elementscontrol, either individually or in combination, may be implemented as acomputer program product tangibly embodied as computer-readable signalson a computer-readable medium, for example, a non-volatile recordingmedium, an integrated circuit memory element, or a combination thereof.For each such method, step, simulation, algorithm, system control, orsystem element control, such a computer program product may comprisecomputer-readable signals tangibly embodied on the computer-readablemedium that define instructions, for example, as part of one or moreprograms, that, as a result of being executed by a computer, instructthe computer to perform the method, step, algorithm, system control,and/or system element control.

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No. 12/679,371 on Sep. 23, 2010, and entitled“Electrolyte Additives for Lithium Batteries and Related Methods”; U.S.Patent Publication No. US 2011/0008531, published on Jan. 13, 2011,filed as application Ser. No. 12/811,576 on Sep. 23, 2010, patented asU.S. Pat. No. 9,034,421 on May 19, 2015, and entitled “Methods ofForming Electrodes Comprising Sulfur and Porous Material ComprisingCarbon”; U.S. Patent Publication No. US 2010/0035128, published on Feb.11, 2010, filed as application Ser. No. 12/535,328 on Aug. 4, 2009,patented as U.S. Pat. No. 9,105,938 on Aug. 11, 2015, and entitled“Application of Force in Electrochemical Cells”; U.S. Patent PublicationNo. US 2011/0165471, published on Jul. 15, 2011, filed as applicationSer. No. 12/180,379 on Jul. 25, 2008, and entitled “Protection of Anodesfor Electrochemical Cells”; U.S. Patent Publication No. US 2006/0222954,published on Oct. 5, 2006, filed as application Ser. No. 11/452,445 onJun. 13, 2006, patented as U.S. Pat. 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U.S. Provisional Application No. 62/785,332, filed Dec. 27, 2018, andentitled “Isolatable Electrodes and Associated Articles and Methods” isincorporated herein by reference in its entirety for all purposes. U.S.Provisional Application No. 62/785,335, filed Dec. 27, 2018, andentitled “Electrodes, Heaters, Sensors, and Associated Articles andMethods” is incorporated herein by reference in its entirety for allpurposes. U.S. Provisional Application No. 62/785,338, filed Dec. 27,2018, and entitled “Folded Electrochemical Devices and AssociatedMethods and Systems” is incorporated herein by reference in its entiretyfor all purposes.

While several embodiments of the present invention have been describedand illustrated herein, those of ordinary skill in the art will readilyenvision a variety of other means and/or structures for performing thefunctions and/or obtaining the results and/or one or more of theadvantages described herein, and each of such variations and/ormodifications is deemed to be within the scope of the present invention.More generally, those skilled in the art will readily appreciate thatall parameters, dimensions, materials, and configurations describedherein are meant to be exemplary and that the actual parameters,dimensions, materials, and/or configurations will depend upon thespecific application or applications for which the teachings of thepresent invention is/are used. Those skilled in the art will recognize,or be able to ascertain using no more than routine experimentation, manyequivalents to the specific embodiments of the invention describedherein. It is, therefore, to be understood that the foregoingembodiments are presented by way of example only and that, within thescope of the appended claims and equivalents thereto, the invention maybe practiced otherwise than as specifically described and claimed. Thepresent invention is directed to each individual feature, system,article, material, and/or method described herein. In addition, anycombination of two or more such features, systems, articles, materials,and/or methods, if such features, systems, articles, materials, and/ormethods are not mutually inconsistent, is included within the scope ofthe present invention.

The indefinite articles “a” and “an,” as used herein in thespecification and in the claims, unless clearly indicated to thecontrary, should be understood to mean “at least one.”

The phrase “and/or,” as used herein in the specification and in theclaims, should be understood to mean “either or both” of the elements soconjoined, i.e., elements that are conjunctively present in some casesand disjunctively present in other cases. Other elements may optionallybe present other than the elements specifically identified by the“and/or” clause, whether related or unrelated to those elementsspecifically identified unless clearly indicated to the contrary. Thus,as a non-limiting example, a reference to “A and/or B,” when used inconjunction with open-ended language such as “comprising” can refer, inone embodiment, to A without B (optionally including elements other thanB); in another embodiment, to B without A (optionally including elementsother than A); in yet another embodiment, to both A and B (optionallyincluding other elements); etc.

As used herein in the specification and in the claims, “or” should beunderstood to have the same meaning as “and/or” as defined above. Forexample, when separating items in a list, “or” or “and/or” shall beinterpreted as being inclusive, i.e., the inclusion of at least one, butalso including more than one, of a number or list of elements, and,optionally, additional unlisted items. Only terms clearly indicated tothe contrary, such as “only one of” or “exactly one of,” or, when usedin the claims, “consisting of,” will refer to the inclusion of exactlyone element of a number or list of elements. In general, the term “or”as used herein shall only be interpreted as indicating exclusivealternatives (i.e., “one or the other but not both”) when preceded byterms of exclusivity, such as “either,” “one of,” “only one of,” or“exactly one of.” “Consisting essentially of,” when used in the claims,shall have its ordinary meaning as used in the field of patent law.

As used herein in the specification and in the claims, the phrase “atleast one,” in reference to a list of one or more elements, should beunderstood to mean at least one element selected from any one or more ofthe elements in the list of elements, but not necessarily including atleast one of each and every element specifically listed within the listof elements and not excluding any combinations of elements in the listof elements. This definition also allows that elements may optionally bepresent other than the elements specifically identified within the listof elements to which the phrase “at least one” refers, whether relatedor unrelated to those elements specifically identified. Thus, as anon-limiting example, “at least one of A and B” (or, equivalently, “atleast one of A or B,” or, equivalently “at least one of A and/or B”) canrefer, in one embodiment, to at least one, optionally including morethan one, A, with no B present (and optionally including elements otherthan B); in another embodiment, to at least one, optionally includingmore than one, B, with no A present (and optionally including elementsother than A); in yet another embodiment, to at least one, optionallyincluding more than one, A, and at least one, optionally including morethan one, B (and optionally including other elements); etc.

In the claims, as well as in the specification above, all transitionalphrases such as “comprising,” “including,” “carrying,” “having,”“containing,” “involving,” “holding,” and the like are to be understoodto be open-ended, i.e., to mean including but not limited to. Only thetransitional phrases “consisting of” and “consisting essentially of”shall be closed or semi-closed transitional phrases, respectively, asset forth in the United States Patent Office Manual of Patent ExaminingProcedures, Section 2111.03.

1. An article, comprising: a substrate; a plurality of discreteelectrode segments adjacent to the substrate, the electrode segmentscomprising electrode active material; and a current collector domaincomprising: a current collector bus, the current collector buselectronically coupled to the discrete electrode segments; and aplurality of current collector segments, each current collector segmentelectronically coupled to an electrode segment, wherein, for each of thecurrent collector segments, the current collector segment iselectronically coupled to the current collector bus via at least onecurrent collector bridge.
 2. The article of claim 1, wherein for eachdiscrete electrode segment, the discrete electrode segment iselectronically coupled to the current collector bus via at least onecurrent collector segment.
 3. The article of claim 1, wherein for eachcurrent collector segment, the current collector segment is disposed, atleast partially, between the substrate and the electrode segment towhich the current collector segment is electronically coupled. 4-12.(canceled)
 13. The article of claim 1, wherein the article is configuredsuch that, when the article reaches a threshold current, at least one ofthe current collector bridges is mechanically deformed such that acurrent collector segment coupled to that current collector bridge is nolonger electronically coupled to the current collector bus. 14-15.(canceled)
 16. The article of claim 13, wherein the threshold currenthas a value greater than or equal to 10 A.
 17. The article of claim 13,wherein the threshold current has a value of less than or equal to 120A.
 18. The article of claim 1, further comprising a heater adjacent tothe substrate configured to heat at least a portion of the substrate.19-240. (canceled)
 241. A method, comprising: heating at least a portionof an electrochemical device using a heater that is a part of theelectrochemical device, the electrochemical device comprising: asubstrate, a plurality of discrete electrode segments adjacent to thesubstrate, the electrode segments comprising electrode active material,and a current collector domain comprising a collector bus, the currentcollector bus electronically coupled to the discrete electrode segments.242. The method of claim 241, wherein the heater is adjacent to thesubstrate.
 243. The method of claim 241, wherein the heater isimmediately adjacent to the substrate.
 244. The method of claim 241,wherein the heating step is initiated, at least, in part, in response toa signal from one or more sensors.
 245. The method of claim 244, whereinthe one or more sensors are a part of the electrochemical device. 246.The method of claim 244, wherein the one or more sensors are adjacent tothe substrate.
 247. The method of claim 244, wherein the heater and/orone or more sensors comprises a thin film.
 248. A method, comprising:detecting a condition of an electrochemical device based, at least inpart, on a signal from a sensor that is a part of the electrochemicaldevice, the electrochemical device comprising: a substrate, a pluralityof discrete electrode segments adjacent to the substrate, the electrodesegments comprising electrode active material, and a current collectordomain comprising a current collector bus, the current collector buselectronically coupled to the discrete electrode segments.
 249. Themethod of claim 248, wherein at least one of the sensors is atemperature sensor and the condition is a temperature.
 250. The methodof claim 248, wherein at least one of the sensors is a pressure sensorand the condition is a pressure. 251-279. (canceled)